UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


OUR  OWN   WEATHER 


OUR    OWN 
WEATHER 


A   SIMPLE    ACCOUNT    OF  ITS   CURIOUS 

FORMS,  ITS   WIDE   TRAVELS,  AND 

ITS     NOTABLE     EFFECTS 

BY 

EDWIN  C.  MARTIN 


ILLUSTRATED 


HARPER  &   BROTHERS   PUBLISHERS 

NEW   YORK    AND    LONDON 

MCMXIII 


P-N 


CHAP. 


Engineering  ft 
Mathematical 

Sciences 
Lihrwy 

QC 

323 


CONTENTS 


. 

I.  A  WORD  IN  COMMENDATION  OF  OUR  WEATHER        i 

II.  THE  WEATHER  AT  LARGE     ........      " 

The  Trade-winds—  The  Effect  of  the  Earth's 
Rotation 

III.  A  GLANCE  AT  THE  ATMOSPHERE   ......      25 

The  Constitution  of  the  Atmosphere—  Extent 
and  Temperature  of  the  Atmosphere 

IV.  THE  CONFLICT  BETWEEN  LAND  AND  WATER  .    .      37 

How  Far  Down  Land  and  Sea  Warm  —  Perma- 
nent Hot  and  Cold  Piles  in  the  Atmosphere 

V.  THE  BODY  THAT  GATHERS  IN  THE  AIR  AND  MAKES 

THICK  WEATHER    .........      49 

The  Setting  Up  of  a  Cyclone  —  The  Difference 
between  a  Cyclone  and  a  Tornado  —  The  Size 
and  Frequency  of  Cyclones  —  The  Form  and 
the  Qualities  of  a  Cyclone 

VI.  How  THE  STORM  BODIES  TRAVEL  AND  Do  THEIR 

WORK  .............      67 

The  Speed  of  Cyclones  —  Change  in  Winds  and 
Temperature  at  the  Approach  of  a  Cyclone  — 
How  the  Cyclone  Produces  Rain 

VII.  THE  BODY  THAT  SCATTERS  THE  AIR  AROUND  AND 

MAKES  FAIR  WEATHER  .......      97 

Form  and  Movements  of  the  Anticyclone  —  How 
Cyclones  and  Anticyclones  Work  Together  — 
A  Country-wide  Weather  Procession 


CONTENTS 

CHAP.  PAGE 

VIII.  THE  WEST  INDIAN  HURRICANE  AND  ITS  PART 

IN  OUR  WEATHER .119 

What  Confines  the  Hurricane  to  a  Given  Season 
and  Course — The  Hurricane's  Path  and  Speed 
— Constitution  and  Behavior  of  the  Hurricane 
— The  Hurricane  as  It  Operates  in  the  United 
States — Storms  that  Broke  All  Records 

IX.  WINTER  AND  SUMMER  WEATHER 138 

Distribution  of  January  Weather — Distribution 
of  July  Weather — The  Passage  from  Winter 
into  Summer 

X.  HOT  AND  COLD  WAVES,  AND  OTHER  EXCESSES  OF 

THE  SEASONS 159 

The  Cold  Wave— The  Hot  Wave— Mild  Sea- 
sons and  Hard  Seasons — Unexplained  Varia- 
tions of  the  Atmosphere — Does  the  Nature  of 
the  Seasons  Change? 

XI.  THE  WINDS 181 

The  Winds  in  the  Different  Parts  of  the  Coun- 
try— Sea-breezes  and  Cyclonic  Winds — The 
Velocity  of  the  Wind — Special  Winds — The 
Chinook— The  Higher  We  Go,  the  Stronger    , 
the  Wind 

XII.  CLOUDS  AND  SUNSHINE 198 

The  Ordinary  Midday  Cloud — Fog — Evening 
Clouds — The  Highest  Clouds — Storm-clouds 
—The  Colors  of  the  Clouds  and  the  Sky 

XIII.  DEW  AND  FROST,  RAIN  AND  SNOW     .    .    .'   .    220 

Dew  and  Frost — The  Form  and  Habits  of  the 
Rain  —  Distribution  of  the  Rain  over  the 
Country — Snow  and  Its  Fall  and  Distribu- 
tion— Hail-storms — Droughts  and  Floods 


CONTENTS 

CHAP.  PAGE 

XIV.  THUNDER-STORMS  AND  TORNADOES 241 

The  Spread  of  a  Thunder-storm  Epidemic — 
"Heat"  Thunder-storms — The  Lightning  in 
Thunder-storms    and    Its    Fatality — The 
Tornado 

XV.  WEATHER  SIGNS  AND  SUPERSTITIONS    ....    259 

The  Moon  and  the  Weather — Men  and  Things 
as  Barometers — The  Barometer  Signs — 
When  the  Rain  Begins — The  Wind  as  a 
Warning  of  the  Weather— Cloud  Signs— The 
Weather  and  the  Colors  of  the  Sky — Con- 
clusion 

INDEX       277 


ILLUSTRATIONS 

FAIR-WEATHER  CLOUDS Frontispiece '     , 

THE   HIGHEST  CLOUDS    (CIRRUS)          Facing  p.    26 

CIRRUS  CLOUDS  DIFFUSED  INTO  A  VEIL,  OR  HAZE     .        "  58 

A  TYPICAL  CYCLONE,   OR   "LOW,"   ON  ITS  JOURNEY 
ACROSS   THE   CONTINENT: 

I.  AT   STARTING   ON   THE   PACIFIC  COAST         .      Page        87 

II.  AT  THE  END  OF  THE  FIRST  DAY'S  JOURNEY  89 

III.  AT     THE     END     OF     THE     SECOND     DAY'S 

JOURNEY "  91 

IV.  AT  THE  END  OF  THE  THIRD  DAY'S  JOURNEY  ' '   93 

V.  END  OF  THE  JOURNEY  AT  THE  ATLANTIC 

COAST "   95 

A  TYPICAL  ANTICYCLONE,  OR  "HIGH,"  CROSSING 
THE  COUNTRY: 

I.  FIRST  APPEARANCE  IN  THE  NORTHWEST  .     "      113 

II.  AT  THE  END  OF  THE  FIRST  DAY'S  JOURNEY  115 

III.  AT    THE    END    OF    THE    SECOND    DAY*S 

JOURNEY "  117 

A   MACKEREL   SKY Facing  p.  144^' 

CUMULUS,    OR    HEAPED-UP,    CLOUDS    BROKEN    AND 

SCATTERED   BY   THE   WIND "  182  Y 

LAYER,   OR   SHEET,   CLOUD    (STRATUS) "  204 

RAIN  CLOUD,   OR   NIMBUS "  2241 

THUNDER-STORM,   OR   SHOWER,   CLOUDS      ....  "  246  > 


OUR   OWN   WEATHER 


OUR  OWN  WEATHER 


A    WORD    IN    COMMENDATION    OF   OUR    WEATHER 

'"THE  weather  itself  is  but  an  activity.  The 
1  air  of  the  atmosphere,  like  the  water  of  the 
sea,  and,  indeed,  like  all  nature,  including  man,  is 
forever  seeking  ease  and  never  quite  finding  it. 
The  weather  is  simply  the  air's  business — its 
runnings  to  and  fro,  its  conflicts  and  avoidances, 
its  unions  and  divisions  and  graspings  and  giv- 
ings-up  in  pursuit  of  this  one  aim  which  it  never 
fully  achieves.  If  expanses  of  atmosphere  were 
as  open  to  view  as  expanses  of  sea  the  slightest 
brushes  of  weather  would  be  all  the  time  giving 
us  intimation  of  a  vastness,  a  puissance,  and  a 
mystery  far  exceeding  the  sea's. 

Our  never  failing  to  find  attraction  in  the  sea 
has  led  us  to  speak  of  it  as  having  a  spell.     One 
i 


OUR   OWN    WEATHER 

might  seem  to  be  pressing  the  matter  pretty  far 
to  claim  for  the  atmosphere,  considered  by 
itself,  that  it  had  a  spell.  But  certainly  in  the 
weather,  the  all-pervasive  product  of  the  atmos- 
phere and  almost  the  only  thing  by  which  the 
atmosphere  is  known  to  us,  on^  may  without 
extravagance  claim  to  find  a  spell.  It  is  a  spell 
all  the  stronger,  all  the  more  enticing,  because  of 
the  meager  visibility  of  the  matter  in  which  it 
lies. 

I  sit  before  an  open  window  that  frames  in  for 
me  the  top  of  a  handsome  tree.  Whenever  I 
lift  my  eyes  I  catch  a  little  spur  and  refreshment 
from  the  flutter  and  sway  revealed  to  me  in 
clusters  of  leaves  and  branchlets.  Most  times, 
in  any  thought  I  may  chance  to  give  to  it,  I  con- 
fine the  movement  wholly  to  the  tree.  If  I  defi- 
nitely ally  it  with  the  tree  it  gains  appreciably 
in  pleasantness  and  interest.  But  if  I  go 
farther,  as  I  may,  and  ally  the  movement  as 
definitely  with  the  other  factor  in  it — the 
breeze — I  am  soon  on  a  pursuit  that  may  easily 
become  a  perfect  fascination.  The  tree  itself 
is  not  without  fascination.  Its  beauty  of  color 
and  of  form,  its  aspect  of  lightness  and  suffi- 
ciency, the  sense  of  its  great,  sure  growth  in 
such  quietness  and  out  of  sources  largely 


A   WORD    IN    COMMENDATION 

obscure,  combine  to  produce  in  one  a  feeling  of 
weirdness  and  enchantment.  Nothing  could 
be  more  natural  than  for  the  old  fairy-tale- 
tellers to  shut  their  enchanted  human  beings 
up  in  the  trunks  of  trees.  Sit  for  a  little  while 
looking  intently  at  a  great  tree  and  you  will 
feel  just  such  a  fate  coming  fell  upon  yourself. 

But  no  tree  can  work  the  wonders  for  you, 
send  through  you  the  rills  of  undefined  delight, 
give  you  the  far-off  glimpses  and  visions  that 
the  breeze  can  if  you  lend  it  your  full  fancy. 
And  yet  the  breeze  is  weather  in  one  of  the 
lightest  of  its  exertions.  Half  the  spell  of  the 
sea  itself  is  after  all  only  the  spell  of  the  weather. 
Take  from  the  sea  all  that  the  weather  imparts 
to  it  in  the  way  of  movement  and  color,  and  it 
would  be  a  pretty  dull,  tame  affair.  Indeed, 
without  the  weather  all  nature,  all  life,  if  life 
there  still  were,  would  be  a  dull,  tame  affair. 

The  weather  ought  not  to  fail  of  interest  in 
any  country  on  the  globe.  But  there  are  good 
reasons  why  our  own  weather  should,  at  least 
to  ourselves,  particularly  abound  in  it.  Ours  is, 
to  begin  with,  a  weather  of  great  variety.  We 
complain  of  this  sometimes  when  two  kinds 
succeed  each  other  with  a  certain  brusqueness. 
But  it  is  not  a  genuine  grievance  with  us.  Let 
3 


OUR    OWN    WEATHER 

autumn  loiter  on  into  the  middle  of  winter,  or 
winter  b,lot  out  spring  and  then  break  abruptly 
off  into  full  summer,  and  the  complaints  we 
make  are  those  of  people  who  feel  that  a  radical 
injustice  has  been  done  them. 

We  are  not  simple  in  either  our  nature  or  our 
habits.  We  should  not  be  content  to  live  under 
the  trees  in  continuous  warmth  or  in  ice  huts 
under  continuous  cold.  We  demand,  indeed, 
at  least  four  good,  well-marked  seasons  and  a 
fairly  active  exchange  month  by  month,  and 
even  day  by  day,  between  fair  weather  and  foul. 
How  far  in  this,  as  in  so  many  other  matters, 
our  luxuriousness  has  arisen  from  the  mere 
possession  of  luxury  rather  than  from  some- 
thing quite  special  and  fine  in  our  own  prime 
creation,  it  would  be  hard  to  say.  But  the 
luxuriousness  itself  is  indisputable;  and  the 
weather,  on  the  whole,  meets  our  sumptuous 
exactions  with  generosity. 

While  abundant  in  variety,  our  weather  is  not, 
however,  in  this  pre-eminent.  The  weather  of 
some  other  countries  has  as  much  or  perhaps 
even  more.  Nor  does  ours,  as  a  whole,  enjoy 
a  clear  superiority  to  the  weather  of  all  other 
countries  in  either  one  of  the  two  primary 
qualities  of  weather,  temperature  and  moisture. 
4 


A   WORD    IN    COMMENDATION 

It  is  neither  the  hottest  nor  the  coldest  nor  the 
wettest  nor  the  dryest  weather  in  the  world. 
The  United  States  do  hold,  though,  at  the 
present  time,  I  believe,  the  world's  record  for 
the  highest  absolute  heat.  At  Mammoth  Tank, 
California,  in  the  Colorado  Desert,  on  August 
17,  1885,  a  temperature  of  130  degrees  in  the 
shade  was  recorded.  This  record  was  repeated 
at  Volcano,  in  the  same  locality,  in  June,  1896. 

Neither  of  these  is  a  Weather  Bureau  record, 
and  they  may  require  a  little  discount  for  that 
reason.  But  a  record  of  128  degrees  made  in 
the  same  month  and  year  as  that  at  Volcano, 
but  at  another  place  in  the  same  region — Salton 
— has  the  Weather  Bureau's  indorsement.  A 
record  of  127.4  degrees  in  Algeria,  on  the  north- 
ern edge  of  the  Desert  of  Sahara,  is  commonly 
named  as  the  highest  yet  made  in  any  other 
quarter  of  the  world.  The  region,  though,  in 
which  with  us  anything  like  these  high  records 
ever  becomes  possible  is  very  small — one  little 
corner  of  Arizona  and  one  little  corner  of 
California — and  offers  in  its  own  weather  no 
real  sample  of  that  of  the  country  at  large. 

We  have  also  some  noteworthy  records  of 
absolute  cold.  The  lowest  are  63.1  degrees 
below  zero  at  Poplar  River,  Montana,  in  Janu- 
5 


OUR   OWN    WEATHER 

ary,  1885,  and  65  degrees  below  zero  at  Fort 
Keogh,  Montana,  in  January,  1888.  But  these, 
like  the  highest  records  of  absolute  heat,  are 
merely  local.  Even  the  one  state  in  which  they 
both  occur  is  not  truly  represented  in  them. 
It  is  not  our  coldest  section.  Northern  Minne- 
sota is  the  region  of  lowest  mean  temperature 
in  the  United  States;  and  the  lowest  tempera- 
ture on  record  there  is  59  degrees  below  zero 
at  Leech  Lake  Dam,  February  29,  1889. 
Even  at  65  degrees  below  zero,  though,  we  are 
not  very  near  the  world's  record  in  low  tem- 
peratures. Siberia  holds  that  with  apparently 
entire  security.  A  temperature  has  been  re- 
corded there  of  90.4  degrees  below  zero,  and  it 
is  in  its  general  temperature  the  coldest  part 
of  the  earth — colder  even  than  the  region 
around  the  poles. 

The  same  two  little  corners  of  Arizona  and 
California  that  have  won  us  the  world's  record 
for  absolute  heat  have  won  it  also  in  the  matter 
of  aridity.  They  have  the  smallest  recorded 
rainfall  of  any  places  on  earth.  But  this  is 
almost  as  pronouncedly  only  their  own  little 
affair  as  is  their  unequaled  warmth.  There  is, 
indeed,  in  the  United  States  a  large  region  of 
scant  rainfall — that  extending  from  the  northern 
6 


A   WORD    IN    COMMENDATION 

to  the  southern  boundary  of  the  country  and 
from  the  Sierra  Nevada  and  Cascade  Moun- 
tains on  the  west  to  a  line  beginning  in  the 
eastern  part  of  North  Dakota  and  running 
almost  directly  south  down  to  and  through  the 
middle  of  Texas.  But  owing  to  the  fact  that  the 
bulk  of  the  fall  is  just  at  the  time  when  rain  will 
be  of  most  service,  a  large  part  of  the  region  is, 
as  we  know,  very  productive.  East  of  this,  over 
all  the  country  to  the  Atlantic  Ocean,  the 
ordinary  rainfall  is  such  that  scarcely  in  all  the 
world  is  there  to  be  found  another  such  extent 
of  territory  so  amply  and  yet  so  moderately 
and  so  evenly  rained  upon.  Of  excessive  rain- 
fall the  country  supplies  at  no  point  records 
of  the  premium  order.  Eccentric  annual  falls 
of  something  over  one  hundred  and  forty  inches 
are  talked  about ;  but  they  cut  no  figure  beside, 
for  instance,  the  records  of  nearly  five  hundred 
inches  of  annual  fall  that  are  reported  from 
India. 

A  country  covering  more  than  three  million 
square  miles  and  of  such  diversity  as  ours  could 
not  fail  to  offer  specimens  of  about  all  the  kinds 
of  weather  that  ever  befall.  Records  like  those 
just  recited  show  that  the  United  States  do  this 
with  quite  the  expected  amplitude.  But  the 
7 


OUR   OWN    WEATHER 

point  of  truly  great  note  and  interest  is  that, 
notwithstanding  many  and  often  the  extremest 
diversities,  we  still  have  a  weather  that  we  can 
properly  call  our  own,  a  weather  peculiar  to  the 
country  and  common  to  the  whole  of  it.  Of  not 
less  note  and  interest,  though,  is  the  fact  that 
this  weather  has  a  comparatively  simple  and 
perfectly  determinable  character.  It  does  not 
blot  out  the  seasons:  in  every  part  of  the 
country  we  have,  more  or  less  well  marked, 
a  winter,  a  spring,  a  summer,  and  an  autumn. 
It  does  not  extinguish  the  differences  between 
northern  and  southern  latitudes:  Texas,  for 
example,  will  always  show  year  by  year  as  on 
an  average  some  twenty-five  degrees  warmer 
than  Maine.  It  does  not  remove  the  contrasts 
between  night  and  day  or  those  of  susceptibility 
between  varied  local  exposures.  Day  breeds 
warmth,  night  coolness,  a  greater  warmth  is 
acquired  under  some  exposures  than  under 
others.  What  the  weather  does  do  is  to  main- 
tain clearly  its  own  character  even  in  the  face 
of  such  diversions  and  differences. 

Knowing  of  it,  however,  no  more  than  just 

this,  one  might  get  the  impression  of  it  as  of  a 

sort  of  formless,  impalpable  something,  spread 

out  somewhere  above  us  over  the  whole  country 

8 


A    WORD    IN    COMMENDATION 

and  lying  there  in  a  perennial  and  obstructive 
sluggishness — a  thing  that  merely  kept  the 
natural  and  proper  weather  more  or  less  from 
its  work.  But  that  is  exactly  what  our  weather 
is  not.  Sluggishness  is  its  last  characteristic, 
and  staying  on  is  not  at  all  its  habit.  It  has  its 
intervals  of  relaxation  or  partial  repose;  like 
some  other  activities,  it  shows  less  energy  in 
summer  than  in  winter.  But,  regarded  the 
whole  year  through,  it  is  practically  always  in 
progress. 

It  has,  too,  as  definite  an  organization  and  is 
as  full  of  its  own  vitality  as  any  living  creature. 
It  presents  itself  in  two  forms,  sharply  con- 
trasted but  intimately  interdependent.  In  one 
or  the  other  of  these  it  appears  always  in  some 
far  western  part  of  the  country — often  on  the 
Pacific  coast,  but  oftener  in  the  northern  Rocky 
Mountain  region — and,  by  paths  that  have  come 
to  be  well  marked,  crosses  to  the  Atlantic  coast. 
In  every  small  locality  to  which  it  comes  it 
suffers  modifications,  and  these  modifications 
are  often  of  the  greatest  importance  to  the  lo- 
cality in  which  they  occur.  But  whatever 
reception  different  localities  accord  it,  whether 
hospitable  or  hostile,  whether  they  add  to  it 
or  take  from  it,  and  whatever  they  do  to  it  or  it 
9 


OUR   OWN    WEATHER 

does  to  them,  they  rarely  alter  it  in  its  essential 
form,  and  it  passes  on  from  one  to  another  and 
finally  out  of  the  country  and  off  over  the 
Atlantic  Ocean  with  as  clear  a  character  and 
identity  as  it  had  when  it  first  appeared.  The 
same  two  forms  are  shown  in  the  weather  of 
other  regions  in  the  temperate  zones.  But 
nowhere  else  do  they  have  the  great  extension, 
the  long  length  of  clear,  unbroken  course,  and 
the  strong  persistence  that  they  have  in  the 
United  States.  And  this  it  is  that  gives  special 
distinction  to  our  weather  and  makes  it  truly 
a  national  weather  and  truly  ours. 

But,  while  our  weather  is  national,  it  is  the 
weather  of  a  nation  of  the  first  class  and  of  a 
people  highly  civilized.  Though  national,  it 
is  not  provincial.  Like  our  political  institu- 
tions and  administration  and  our  commerce, 
it  has  its  world  connections,  and  it  would 
hardly  be  quite  worthy  of  us  if  it  did  not  have 
them.  To  apprehend  it  in  its  real  peculiarities 
and  in  the  full  magnitude  of  its  manifestations 
requires  some  attention  also  to  the  weather  at 
large. 


II 

THE    WEATHER    AT    LARGE 

OF  all  weather,  through  however  long  a 
genealogy,  the  first  father  is,  of  course,  the 
sun.  That  great  molten  body,  more  than  three 
hundred  thousand  times  as  large  as  the  earth, 
is  always  giving  off  on  all  sides  into  space  a 
something  of  which  we  hide  what  remains  as  yet 
a  nearly  complete  ignorance  by  calling  it  solar 
radiance,  or  solar  energy,  or  simply  sunshine. 
The  earth,  lying  in  line,  is  constantly  smitten 
by  some  few  shreds  of  this  vast  outgiving — a 
two-billion-two-hundred-millionth  part,  to  be 
devoutly  exact.  This  seems  a  trifling  amount; 
but  it  would  suffice,  if  all  diverted  for  the  mo- 
ment into  such  needless  tasks,  to  boil  quanti- 
ties of  water  or  lift  amounts  of  weight  wholly 
inconceivable  by  us  even  when  we  have  the  very 
figures  before  us :  as,  for  instance,  to  carry  in  a 
minute  thirty-seven  billion  tons  of  water  to  the 
boiling-point  from  the  freezing. 


OUR   OWN    WEATHER 

This  energy  or  radiance,  this  sunshine,  comes 
in  undulating  beams,  or  rays,  of  different 
wave-lengths,  but  otherwise  all  alike,  and  in 
open  space  traveling  always  at  the  same 
velocity — a  little  more  than  one  hundred  and 
eighty-six  thousand  miles  a  second.  The  lead- 
ing meteorologists  treat  it  as  also  of  always  the 
same  quantity  or  force;  but  there  is  now  going 
on  a  keen  discussion,  along  with  much  careful 
investigation,  on  that  very  point.  The  sun- 
spot  theory,  of  which  the  newspapers  keep  us 
in  constant  attention,  now  seriously,  now  sport- 
fully, is  the  most  definite  branch  of  this  discus- 
sion, the  question  being  whether,  when  the 
sun's  spots  are  most  displayed,  its  radiance,  or 
energy,  is  diminished. 

Whether  the  amount  of  solar  energy  arriving 
at  the  borders  of  the  earth's  atmosphere  be  or 
be  not  always  the  same,  certainly  the  earth's 
and  the  atmosphere's  exposure  to  it  is  always  in 
change.  The  earth,  by  its  daily  rotation  on  its 
axis,  enjoys  the  sun's  radiance  first  on  one  side 
and  then  on  the  other,  with  a  result  marked 
to  us  unmistakably  in  the  alternations  of  day 
and  night.  Then,  while  submitting  itself  to 
the  sun's  radiance  by  sides  or  strips,  the  earth 
in  its  yearly  revolution  around  the  sun  submits 


THE   WEATHER   AT    LARGE 

itself  to  the  same  influence  also  by  belts  or 
bands.  The  very  eye  of  the  sun  is,  in  effect, 
made  to  traverse  it  up  and  down  from  a  line 
sixteen  hundred  miles  south  of  the  equator 
(the  tropic  of  Capricorn)  to  a  line  sixteen  hun- 
dred miles  north  of  the  equator  (the  tropic  of 
Cancer).  Of  this  the  effect  is  marked  to  us  by 
the  alternations  of  the  seasons.  Such  large 
variations  of  exposure  produce,  in  both  the 
earth  and  the  atmosphere,  corresponding  vari- 
ations of  temperature.  In  the  atmosphere 
variations  of  temperature  easily  become  con- 
trarieties; and  these  and  the  effort  to  adjust 
them  make  the  weather. 

Since  nothing  more  regular  is  known  to  us 
in  all  the  universe  than  the  two  motions  of  the 
earth  that  determine  its  exposure  to  the  sun, 
we  might,  if  ever  we  got  our  conception  of  the 
weather  from  the  all-familiar  primary  facts 
regarding  it,  expect  it  to  be  fairly  regular  also. 
It  does,  in  fact,  maintain  a  considerable  regu- 
larity in  its  rudimentary  manifestations.  In 
the  region  of  the  equator,  where  the  days  and 
nights  are  always  of  equal  length  and  where  the 
rays  of  the  sun  fall  always  with  greater  direct- 
ness than  on  any  other  part  of  the  earth,  the 
air  is  always  becoming  hotter  and  more  ex- 
13 


OUR   OWN    WEATHER 

panded  than  anywhere  else;  and  the  colder, 
more  condensed  air  about,  being  under  a  greater 
pressure  of  gravity,  is  always  pushing  in,  ready, 
like  any  other  over-pressed  thing,  to  get  more 
space  for  itself.  The  hot  air  is  thus  forced 
aloft.  Wherever  it  can  find  points  of  escape 
it  drifts  off  on  either  side  toward  the  poles. 
Always  cooling  as  it  goes  and  mingling  with 
other  masses  of  air  that  will  receive  it,  it  be- 
comes itself  a  part  of  the  more  condensed  and 
pulled-upon  body  and  gradually  descends  and, 
as  far  as  it  may,  roots  its  way  back  toward 
the  region  in  which  it  ascended.  For  particular 
particles,  though,  to  return  to  just  the  place 
they  started  from,  if  it  ever  happens,  must  be  a 
very  rare  occurrence.  The  exchange  is  un- 
ceasing, and  all  the  way  from  the  equator  to  the 
poles  it  proceeds  with  a  sufficient  regularity 
to  maintain  a  well-marked  system  of  winds, 
winds  being  nothing  but  defined,  more  or  less 
horizontal  movements  of  the  air,  as  currents 
are  of  water. 

The  Trade-winds 

Of  these  far  the  most  regular  are  the  trade- 
winds  of  the  tropics.     They  so  contrast  with 
what  we  who  live  in  other  regions  know  by  our 
14 


THE   WEATHER   AT    LARGE 

own  experience  of  wind  that  they  have  acquired 
a  great  fame  and  an  interest  thoroughly  roman- 
tic. The  very  name  of  trade- winds  quickens 
the  fancy.  Poets  have  delighted  to  sing  of 
them,  and  the  school  of  sea-romancers  could 
scarcely  have  lived  without  them.  They  begin 
— both  north  and  south  of  the  equator— near 
the  thirtieth  parallel  of  latitude^the  parallel 
tnat  in  the  north  marks  a  part  of  ourownborder 
along  the  Gulf  of  Mgjacp.  By  the  time  the 
"colder  air  from  outside  regions  reaches  the  sur- 
face in  the  tropics  it  has  become  itself  pretty 
well  heated.  There  is  ordinarily  just  enough, 
difference  of  temperature  between  the  invading 
andthe  displaced  currents  to  effect  a  displace- 
ment. 

The  trade-winds  are  the  movements  of  these 
invading  currents.  Jl;hey  extend  from  the  sur- 
face of  the  earth  up  to  an  averageTieighToTabout 
Two  niileij. — They  are  Commonly  bn§k_jBands, 
but  almgst  neverviolent!  They  have  their 
lulls  and  shifts;  but  these  are  few  and  slight, 
and  often  for  days  and  even  weeks  at  a  time 
they  blow  without  showing  in  either  their 
direction  or  their  force  any  notable  variation. 
North  of  the  equator  they  blow  always  from 
the  northeast;  south  of  the  equator  always 
15 


OUR   OWN    WEATHER 

from  the  southeast.  They  are  more  pronounced 
in  the  winter  of  their  region  than  in  the  summer, 
but  they  have  at  no  time  in  the  whole  year  any 
real  cessation. 

The  two  fields  of  trade-wind  activity  —  the 
one  mainly,  but  not  quite  exclusively,  north  of 
the  equator  and  the  other  mainly,  but  not  quite 
exclusively,  south  —  extend 


earth  in  fairly  well-marked  belts.^  Within  these 
belts  lie  Mexico  and  the  \Vest  Indies,  the  larger 
part  of  South  America,  a  good  big  fraction  of 
the  Atlantic  Ocean,  most  of  Africa,  of  Arabia, 
and  of  India;  the  whole  of  the  Indian  Ocean; 
southern  China,  northern  Australia,  the  Dutch 
East  Indies,  the  Philippines,  and  a  good  big 
fraction  of  the  Pacific  Ocean.  The  two  to- 
gether cover,  indeed,  about  one-half  of  the 
earth's  surface.  The  regions  comprehended  in 
tEem  are  largely  pure  ocean  region  .^.  and  it  is 
only  in  these  that  the  trade-winds  fully  justify 
their  reputation  of  being  the  most  regular  winds 
and  providing  the  most  constant  weather  in 
the  world.  The  moment  land  intrudes  there 
arise  diversions  and  transformations,  and  these 
have  within  their  limits  often  an  importance 
quite  equal  to  that  of  the  main  movement.  It 
is  due  to  continental  intrusions,  for  example, 
16 


THE   WEATHER   AT    LARGE 

that  the  trade-winds,  both  northern  and  south- 
ern, set  in  at  points  considerably  farther  from 
the  equator  on  the  east  side  of  the  Atlantic  and 
Pacific  oceans  than  on  the  west  side,  and  that 
they  show  their  greatest  strength  in  the  south 
Indian  Ocean. 

All  the  grand  divisions  of  the  atmosphere, 
and  with  them  the  permanent  winds,  shift  their 
ground  somewhat  under  the  yearly  variation 
in  the  earth's  exposure  to  the  sun.  The  trade- 
winds  exhibit  this  characteristic  with  as  much 
clearness  as  they  do  those  more  peculiar  to  them. 
When,  as  we  commonly  express  it,  the  sun  is 
coming  north  the  two  trade-wind  belts  follow 
it  northward;  and  as  the  sun  goes  south  they 
faithfully  turn  about  and  follow  it  southward. 
The  range  of  this  movement  is  different  in  differ- 
ent sections  of  the  belts,  being  in  some  as  little 
as  two  hundred  and  in  others  as  much  as  six 
hundred  miles.  At  its  utmost  it  is  about  twenty- 
six  hundred  miles  less  than  the  sun's  own  range. 

In  this  movement  is  included  a  belt  of  at- 
mosphere that  is  not  itself  a  trade-wind  region. 
Before  the  trade- winds  from  the  north  and  those 
from  the  south  actually  fly  into  each  other's 
faces  the  air  in  them  has  become  so  warm  that 
they  die  out  or  are  extinguished  in  the  ascending 
17 


OUR   OWN    WEATHER 

currents.  In  consequence  of  this  there  is  al- 
ways lying  in  between  them  a  belt  of  air  of 
almost  no  circulation,  known  as  the  belt  of 
equatorial  calm,  or,  more  familiarly,  the  dol- 
drums— the  thing  we  all  of  us  sometimes  get  in, 
even  though  we  stay  out  of  the  tropics.  It 
differs  at  different  seasons  and  in  different  local- 
ities, but  it  maintains  around  the  whole  earth 
and  through  the  entire  year  a  breadth  of  from 
one  hundred  and  fifty  to  six  hundred  miles. 
It  is,  though,  like  the  trade-winds  themselves, 
more  an  ocean  than  a  land  condition,  and  often 
quite  loses  its  character  over  the  land. 

Higher  up  in  the  atmosphere,  just  over  the 
trade-winds,  blow  the  anti-trades,  making,  ap- 
parently, the  other  ha5  ofwhafe^thus  becomes 
all  through  a  ratherdefmite  syst.erp  of  air 
J:irculalAOTr — Tlltitr  direction  is  exactly  the 
opposite*  of  that  of  the  trades — from  the  south- 
west on  the  north  side  of  the  equator  and  from 
the  northwest  on  the  south  side.  At  the  point 
where  these,  the  upper,  winds  lose  their  identity 
and  where  the  lower,  or  trade,  winds  begin  to 
exhibit  theirs — that  is  to  say,  about  the  thirtieth 
parallel  of  latitude,  both  north  and  south  of  the 
equator — is  another  belt  of  calm.  The  pair  are 
known  as  the  tropical  belts.  They  are  not  so 
18 


THE    WEATHER    AT    LARGE 

clearly  marked  as  the  equatorial  belt,  but  it  is  in 
them  rather  more  than  in  the  equatorial  belt  that 
we  find  the  scene  of  those  tales  which,  dealing 
with  ships  tragically  becalmed  and  waterless, 
give  youth  so  often  its  first  relish  of  literary 
entertainment.  Back,  indeed,  to  such  tales  is 
to  be  referred  another  name  these  belts  have — 
that  of  the  Horse  Latitudes.  The  name  would 
seem,  though,  to  belong  in  strictness  only  to  the 
northern  belt ;  for  the  account  commonly  given 
of  its  origin  is  that  vessels  carrying  cargoes  of 
horses  from  New  England  to  the  West  Indies 
were  so  often  caught  in  tropical  calms  and 
compelled  by  the  shortening  supply  of  fresh 
water  to  cast  some  of  the  horses  overboard  as  to 
make  the  region  a  byword  for  this  experience. 
Owing  in  some  way  to  the  turns  and  conflicts 
of  the  general  circulation,  the  atmosphere  shows 
within  the  tropical  belts  always  a  somewhat 
higher  average  weight,  or  pressure,  than  ap- 
pears in  any  other  latitude.  In  view  of  this 
they  are  often  spoken  of  as  the  belts  of  per- 
manent high  pressure,  and  it  causes  the  weather 
in  the  regions  over  which  they  lie  to  be  prevail- 
ingly fresh  and  clear.  The  equatorial  belt,  on 
the  other  hand,  shows  a  permanently  low  pres- 
sure— the  lowest  average  pressure  shown  any- 
19 


OUR   OWN    WEATHER 

where  except  around  the  poles;  and  it  produces 
in  its  region  weather  prevailingly  close  and 
rainy.  The  northern  belt  of  high  pressure,  as 
will  appear,  plays  an  important  part  in  our  own 
weather. 

The  moment  we  pass  out  of  the  tropics  the 
weather  becomes  even  in  what  are  known  as  its 
permanent  features  a  far  more  mixed  affair. 
The  sun,  even  at  the  midsummer  height  of  its 
advancement,  produces  no  such  equality  of  heat 
through  the  temperate  and  frigid  zones  as 
always  prevails  in  the  torrid  zone ;  and  in  mid- 
winter the  permanent  gradations  of  tempera- 
ture between  the  tropics  and  the  poles  are  yet 
sharper.  Consequently,  the  relations  between 
the  cold  and  the  warm  masses  or  currents  of 
air  become,  outside  of  the  tropics,  much  more 
varied  and  violent.  Below  the  southern  tropical 
belt,  near  the  fortieth  parallel,  there  blows  the 
year  round  from  west  to  east  a  wind  of  such 
fierceness  that  the  sailors  long  ago  named  the 
region  the  Roaring  Forties,  to  the  subsequent 
joy  and  profit  of  the  sea-romancers.  Its  high 
constant  force  is  due  primarily  to  the  fact  that 
it  meets  with  little  land  to  impede  it. 

In  both  hemispheres,  between  the  tropics 
and  the  poles  there  is  always  prevailing  a  west 
20 


THE   WEATHER    AT    LARGE 

or  westerly  wind;  but  in  the  northern  hemis- 
phere, owing  to  the  abundance  and  diversity 
of  land,  it  is  so  often  deflected  or  obscured 
that  probably  a  large  part  of  the  people  of  the 
United  States  live  all  their  lives  without  ever 
finding  out  that  the  wind  that  brushes  them 
day  by  day  is  prevailingly  from  the  west. 
Except  the  trades,  blowing  from  the  northeast 
on  the  upper  side  of  the  equator  and  from  the 
southeast  on  the  lower  side,  all  of  the  perma- 
nent winds,  whether  lower  or  higher,  tend  to  be 
westerly.  That  is  to  say,  they  tend  to  blow 
always  toward  some  part  of  the  east.  The 
lower  winds,  outside  of  the  trade-wind  zone, 
blow  from  the  northwest  in  the  northern  hemis- 
phere, and  in  the  southern  from  the  south- 
west. 

The  upper  winds — strong  westerly — over  the 
two  temperate  zones  create,  it  is  now  held, 
an  immense  whirl,  or  cyclone,  about  either  pole. 
The  force  of  the  whirl  holds  the  air  back  from 
the  pole,  and  the  atmosphere  shows  at  both 
poles,  as  at  the  equator,  a  permanent  low 
pressure.  Out  of  the  great  polar  cyclones,  it 
is  also  now  sometimes  held,  are  formed,  as  a 
sort  of  satellite,  the  more  ordinary  cyclones 
which,  as  we  shall  see,  are  the  main  makers 
21 


OUR   OWN    WEATHER 

and  unmakers  of  weather  in  the  United  States. 
That  our  own  weather,  while  remaining  strict- 
ly our  own,  has  this  or  some  such  magnificent 
far-off  connection  makes  the  study  of  it  pecu- 
liarly engaging. 

The  Effect  of  the  Earth's  Rotation 

Since  all  of  the  permanent  winds  are  but  re- 
sponses to  the  general  disposition  of  the  air  of 
colder  regions  to  push  down  toward  the  equator 
and  there  to  rise  and  move  toward  the  poles, 
we  might  wonder  why  they  did  not  proceed 
in  their  business  more  directly;  why  they  were 
not,  in  other  words,  straight  north  and  south 
winds.  But  for  that  we  have  all  been  too  well 
schooled.  Who  of  us  can  ever  forget,  after  the 
faithful  way  in  which  it  was  dinned  into  us 
in  our  youth,  that  the  earth,  in  its  daily  rota- 
tion from  west  to  east  on  its  own  axis,  travels 
faster  at  the  equator  than  at  the  poles?  To 
the  less  mathematical  or  mechanical  of  us  it 
may  never  have  become  a  live  and  really  credi- 
ble conception;  but  at  least  we  hold  it  in  im- 
perishable memory  as  a  propounded  fact.  And 
nowhere  does  the  thing  so  eminently  assert 
itself  as  in  the  movements  of  the  air. 
22 


THE   WEATHER    AT    LARGE 

A  body  of  air  traveling  from  the  equator  tow- 
ard the  poles  carries  with  it  an  eastward  speed 
acquired  at  the  equator  and  exceeding  always 
that  which  it  finds  in  the  parts  to  which  it 
goes.  On  the  other  hand,  a  body  of  air  traveling 
from  the  poles  toward  the  equator  carries  with 
it,  acquired  at  its  place  of  starting,  an  eastward 
speed  slower  than  any  that  it  encounters.  The 
result  is  that  all  movements  of  the  air — or,  in 
other  words,  all  winds — of  any  consequence, 
under  stress  of  the  earth's  rotation  and  its 
different  speed  at  different  latitudes,  suffer  a 
twist  or  deflection,  to  the  right  in  the  northern 
hemisphere,  and  to  the  left  in  the  southern, 
from  the  direction  they  were  meaning  to  take. 

To  this  deflection  more  than  to  any  other 
cause  is  due  that  aspect  of  utter  wilfulness 
which  the  winds  show  us  in  our  ordinary  ex- 
perience of  them.  This  has  found  acceptable 
expression  in  the  Biblical  phrase,  "the  wind 
bloweth  where  it  listeth."  But  what  makes 
the  wind  so  generally  incalculable  is  that,  in 
fact,  it  never  does  blow  quite  where  it  listeth. 
Like  a  strong,  persistent  man,  it  usually  arrives, 
gets  something  of  what  it  was  after,  but  not 
without  detours,  resignations,  and  compromises. 
And  since  the  wind  is  much  the  greatest  of  the 
23 


OUR   OWN    WEATHER 

various  atmospheric  activities  that  united  con- 
stitute the  weather,  all  of  its  adversities  and 
behaviors  are  those  of  the  weather  as  well. 
The  wonder  of  the  wind,  that  under  such  great 
perturbations  lies  a  large  fixity  and  order,  is 
the  wonder  also  of  the  weather.  This  will  show, 
though,  as  yet  more  of  a  wonder  if  we  consider 
a  little  the  atmosphere  itself — the  element  in 
which  the  wind  and  the  weather  originate  and 
reside. 


Ill 

A   GLANCE   AT   THE   ATMOSPHERE 

THERE  is  nothing  in  all  nature  of  greater 
interest  to  human  beings  than  the  atmos- 
phere. That  we,  the  human  beings,  do  not 
ourselves  just  find  it  so  is  due,  no  doubt,  largely 
to  the  fact  that  we  see  next  to  nothing  of  it. 
It  sticks  to  the  earth  on  which  we  live  as  tightly 
as  we  ourselves  —  has,  indeed,  as  instinctive 
and  deep  a  dread  as  we  ourselves  have  of  ever 
getting  away.  And  it  sticks  to  us,  to  our  very 
persons,  as  tightly  as  it  sticks  to  the  earth. 
Our  own  skins  are  scarcely  nearer  or  more  con- 
stant to  us.  It  not  only  clothes  us,  but  we  feed 
upon  it.  It  is  as  vital  to  us  as  our  blood.  And 
yet  if  some  unusually  smart  person  or  persons 
had  not  discovered  the  fact  and  told  us  we 
might  never  have  known  of  its  existence.  In 
itself  it  is  practically  never  perceptible  to  us; 
we  see  it  only  through  what  are  known  as  its 
"impurities." 

25 


OUR   OWN    WEATHER 

The  word  "impurities"  has,  when  applied  to 
the  atmosphere,  not  necessarily  the  disparage- 
ment that  it  has  when  applied  to  some  other 
things — say,  to  politics  or  to  personal  conduct. 
Anything  the  atmosphere  contains  that  is  not 
an  essential  part  of  its  constitution  is  classed, 
whether  noxious  or  innoxious,  as  an  impurity. 
It  is  always  something  that  the  atmosphere 
catches  up  from  the  earth.  Perhaps  the  most 
prevalent  of  such  impurities  is  moisture,  or 
water- vapor — one  that  we  could  ill  spare.  The 
others  are  commonly  grouped,  for  convenience, 
under  the  general  name  of  "dust,"  because  they 
are  apt  always  to  have  something  of  the  quality 
of  what  we  ordinarily  know  as  dust.  And  it  is 
only  in  combination  with  either  water- vapor  or 
dust,  or  with  both,  that  the  atmosphere  ac- 
quires the  thickness,  color,  and  glimmer  to 
which  mainly  we  owe  our  sense  of  its  visibility. 

The  Constitution  of  the  Atmosphere 

When,  under  some  rare  prompting,  we  do 
bestow  a  little  attention  on  the  atmosphere  we 
find  that  the  fact  of  its  offering  us  so  little  to 
see  really  enhances  its  wonder.  This  thing 
that  to  our  ordinary  perception  scarcely  exists 
has  as  decided  a  character  and  as  individual  a 
26 


A  GLANCE  AT  THE  ATMOSPHERE 

way  of  life  as  the  most  complex  and  substantial 
animal.  In  every  part  of  the  world,  on  sea,  on 
land,  at  low  levels  and  at  high,  the  matter  of 
it — that  is  to  say,  the  air — retains  with  extraor- 
dinary constancy,  up  at  least  to  a  height  of 
seven  miles,  the  constitution  of  a  shade  under 
twenty-one  parts  of  oxygen  to  a  shade  over 
seventy-eight  parts  of  nitrogen. 

The  air  does  this  in  spite  of  the  fact  that  the 
two  elements  are  only  mixed,  never  chemically 
combined.  The  oxygen  continues  to  be  only 
oxygen,  and  the  nitrogen  only  nitrogen.  If 
they  wrought  strictly  into  each  other,  drank 
or  ate  each  other  up,  and  in  that  way  converted 
themselves  into  air,  then  their  holding  always 
and  everywhere  to  the  one  proportion  might 
seem  less  curious.  Nitrogen,  to  be  sure,  is  a 
very  unsocial,  inert  element,  never  eager  to 
combine  and  always  loth  to  move.  It  has, 
indeed,  so  little  activity  that  scientists  wonder 
sometimes  how  so  much  of  it  ever  got  into  the 
atmosphere  and  how,  if  a  need  arose,  it  would 
ever  get  out.  But  oxygen  is  just  the  opposite; 
it  likes  society  and  change.  The  air,  therefore, 
would  seem  to  be  a  marriage  in  which  the  duller 
and  bulkier  spouse  repressed  and  controlled 
the  gayer  and  more  roving. 
3  27 


OUR   OWN    WEATHER 

There  are  quite  constant  bits  of  other  gases 
in  the  atmosphere  up  to  a  height  of  seven 
miles,  and  a  much  varying  quantity  of  water- 
vapor,  the  latter  playing  an  important  part 
in  the  weather.  From  this  height  upward  the 
air  seems  gradually  to  alter  its  entire  constitu- 
tion. The  nitrogen  and  the  oxygen  dimin- 
ish until,  at  the  height,  say,  of  sixty  miles  they 
entirely  give  out.  What  then  remains  is  a 
something  so  tenuous  that  it  has  no  perceptible 
weight  and  of  which  the  main  constituent  is 
probably  hydrogen,  the  lightest  of  all  known 
substances.  Such  air  would  be  about  as  little 
for  a  human  creature  to  live  on  as  the  promise 
of  a  politician.  Yet  even  this  slight  thing 
may  have  its  shadow  of  influence  on  the 
weather;  no  one  knows. 

Constituted  as  it  is,  the  air  contracts  easily 
and  as  easily  expands.  Heat  quickly  expands 
it ;  cold  as  quickly  contracts  it.  As  it  expands 
it  cools;  as  it  contracts  it  warms.  The  whole 
atmosphere  is  held  fast  to  the  earth  by  the 
earth's  force  of  gravity.  But  the  different  parts 
respond  to  that  force  in  the  most  different 
degrees,  according  as  they  are  nearer  or  farther 
from  the  earth  and  according  as  they  are  more 
compact  or  more  diffused.  The  nearer  or  the 
28 


A  GLANCE  AT  THE  ATMOSPHERE 

more  compact  they  are  the  more  tightly  they 
are  held.  The  lower  layers  have,  besides  the 
earth's  pull  upon  them  directly,  the  further  com- 
pulsion of  its  pull  upon  those  above.  In  other 
words,  they  have  to  bear  not  only  their  own 
weight,  but  that  of  all  the  air  on  top  of  them. 
It  is  a  considerable  burden. 

Extent  and  Temperature  of  the  Atmosphere 

Nobody  knows  how  far  up  the  atmosphere 
extends.  In  just  the  character  that  it  shows 
at  the  surface  of  the  earth  it  continues  probably 
not  more  than  seven  miles.  But  in  some  form 
that  produces  unmistakable  atmospheric  ef- 
fects it  must  continue  much  farther  than  that, 
perhaps  even  as  far  as  a  hundred  miles.  Its 
height  is,  at  any  rate,  enough  to  produce  at  sea 
level,  on  a  surface  one  foot  square,  a  pressure, 
or  weight,  of  about  a  ton.  Under  this  weight 
the  lower  layers  are  therefore  normally  always 
the  more  condensed,  the  more  closely  packed; 
and  because  of  this  closer  packing  they  are  also 
normally  always  the  warmer. 

This  would  be  the  condition  of  any  substance 
piled  high;  but  it  is  immensely  intensified  in 
the  pile  that  makes  the  earth's  atmosphere,  be- 
29 


OUR   OWN    WEATHER 

cause  of  the  peculiar  behavior  of  air  under  the 
shining  of  the  sun.  Pure  air,  while  it  retains 
a  large  fraction  of  the  solar  energy  that  comes  to 
it  and  is,  so  to  say,  thrown  into  heat  by  so  much 
as  it  retains,  has  also  a  strong  disposition  to 
pass  the  energy  on  to  the  earth.  The  land 
parts  of  the  earth,  on  the  other  hand,  are 
perfectly  greedy  of  solar  energy.  They  gulp  in 
all  they  can  get  of  it  and  become  immedi- 
ately drunk  under  it — that  is,  excessively  warm. 
The  earthy  matter — the  "dust" — which  the 
atmosphere  in  its  lower  parts  is  always  catching 
up  has  the  temperament  of  its  origin,  and,  like 
the  land  itself,  greedily  absorbs  solar  energy 
and  grows  correspondingly  warm.  This  alone 
would  make  the  lower  layers  of  the  atmosphere 
commonly  warmer  than  the  higher.  But  they 
acquire  much  heat  also  from  the  earth  itself, 
partly  by  direct  contact  with  the  hot  surface 
and  partly  by  retaining  and  converting  into 
heat  much  of  the  energy  given  off,  or  radiated, 
by  the  earth  when  it  cools,  and  it  cools  as  readily 
as  it  warms. 

Under  the  action   of   these   various   causes 

there  exists  a  difference  of  temperature  between 

the  lower  and  the  upper  parts  of  the  atmosphere 

such  as  hardly  seems  possible.     At  the  height 

30 


A  GLANCE  AT  THE  ATMOSPHERE 

of  six  miles  the  air  is  permanently,  the  year 
round,  colder  than  at  the  surface  of  the  earth 
by  about  100  degrees  (Fahrenheit).  Naturally, 
under  so  great  a  disparity,  the  warm  parts  are 
always  more  or  less  in  contest  with  the  cold 
parts  for  space  and  place.  The  one  heated, 
the  other  cooled  to  the  last  point  of  endurance, 
each  seizes  upon  the  least  opening  offered  by 
the  other  toward  more  grateful  conditions. 

The  contest  is  sharpest  down  where  the  heat- 
ing is  strongest  and  speediest.  The  greater 
storms  may  attain  a  height  of  six  or  seven  miles, 
but  the  main  storm  region  extends  scarcely  as 
high  as  two  miles.  At  the  height  of  seven 
miles  the  temperature  is  so  low  that  most  of  the 
water- vapor  in  the  air  has  condensed  and, 
under  the  weight  of  condensation,  fallen  to 
lower  levels.  All  that  remains  there  is  in  the 
form  of  cirrus  clouds,  clouds  composed  wholly  of 
ice  particles.  From  the  height  of  two  miles 
upward  the  atmosphere  is  apt  to  be  free  of 
clouds,  which  indicates  a  condition  of  much 
stability. 

The   decrease   of   temperature   with   ascent 

is  thus  continuous  and  at  a  fairly  steady  rate. 

Even  in  the  lowest  and  most  troubled  region 

this  order  never  gets  wholly  overthrown.     On 

31 


OUR   OWN    WEATHER 

or  very  near  the  earth  there  are  many  local 
or  momentary  departures  from  it.  There  are 
also  some  general  ones.  In  warm,  clear  weather 
the  temperature  decreases  with  ascent  during 
the  heat  of  the  day,  but  actually  increases  during 
the  coolness  of  early  morning.  In  moist, 
cloudy  weather  it  decreases  unfailingly,  but  at 
a  slower  and  less  certain  rate  than  in  clear 
weather.  But  in  spite  of  all  falters  and  re- 
versals there  is  still  a  prevailing  decrease. 

Careful  observations  made  by  our  own 
Weather  Bureau  at  a  number  of  selected  stations 
in  various  parts  of  the  country  have  shown  that 
in  the  warm  months  the  decrease  is  at  an  aver- 
age rate  of  4.01  degrees  Fahrenheit  per  thousand 
feet  up  to  the  height  of  a  mile.  The  rate  of 
decrease  is  considerably  less  in  winter  than  in 
summer.  In  both  winter  and  summer  it  is 
more  rapid  according  as  the  elevation  is  greater, 
and  it  becomes  considerably  more  rapid  above 
the  height  of  two  miles  than  it  is  below.  Along 
with  increase  in  the  rate  of  loss  of  temperature 
goes,  apparently,  also  an  increase  in  the  veloc- 
ity of  the  winds.  They  have  much  greater 
force  up  near  the  seven-mile  level  than  they 
have  below. 

At  or  near  the  seven-mile  level  we  encounter 
32 


A  GLANCE  AT  THE  ATMOSPHERE 

a  surprise.  The  temperature,  instead  of  con- 
tinuing to  decrease  with  ascent,  remains  prac- 
tically constant  at  67  degrees  below  zero 
(Fahrenheit)  up  as  far  as  definite  observation 
has  yet  extended,  which  is  between  eighteen 
and  nineteen  miles.  The  winds,  too,  continue 
no  longer  to  gain  in  force,  but  are  less  strong 
just  above  the  seven-mile  level  than  just  below 
it.  At  every  increase  of  elevation  from  the 
earth  up  the  air  loses  in  pressure,  or  weight, 
partly  because  of  diminishing  density,  but 
more  because  of  the  diminishing  depth  of  the 
pile.  But  immediately  above  the  seven-mile 
level  the  loss  becomes  much  sharper  than  at 
any  point  below.  At  the  height  of  eighteen 
miles  the  pressure  is  little,  if  any,  more  than 
a  hundredth  part  of  what  it  is  at  the  surface 
of  the  earth. 

All  of  these  alterations  setting  in  so  suddenly 
above  the  seven-mile  level  are  thought  to  be 
due  to  as  sudden  a  change  in  the  constitution 
of  the  air  itself,  to  especially  a  large  loss  in 
nitrogen  and  oxygen  and  an  accession  of  hy- 
drogen. The  line  or  plane  of  alteration  seems 
to  be  everywhere  well  defined,  but  it  has  not 
everywhere  the  same  elevation.  All  levels  of 
vertical  change  in  the  atmosphere  tend,  indeed, 
33 


OUR   OWN    WEATHER 

to  be  higher  at  the  equator  and  to  lower  in 
proportion  as  they  approach  the  poles.  It  is 
mainly  as  they  have  been  observed  in  our  own 
latitude — the  latitude  of  the  temperate  zone — 
that  such  levels  are  spoken  of  here. 

Because  of  its  nearly  constant  temperature 
the  atmosphere  from  the  seven -mile  level 
upward  is  known  as  the  "isothermal"  (equal 
temperature)  region.  It  is  sometimes  spoken 
of  also  as  the  region  of  inversion,  under  the  idea 
that  there  the  temperature  not  only  no  longer 
decreases  with  ascent,  but  even  somewhat 
increases.  Not  much  is  known  of  it  as  yet; 
but  by  means  especially  of  kites  and  balloons 
we  are  all  the  time  coming  to  know  a  little  more. 
By  kites,  altitudes  of  only  about  two  miles  are 
reached ;  but  by  balloons  altitudes  of  more  than 
eighteen  miles  have  been  achieved.  For  the 
higher  flights  a  small  rubber  balloon,  equipped 
with  automatically  recording  instruments,  is 
used.  As  the  balloon  mounts  into  rarer  and 
rarer  air  it  finally  reaches  a  point  where  the 
pressure  of  the  gas  confined  in  it  so  exceeds  the 
pressure  of  the  air  around  it  that  it  bursts. 
A  light  parachute  with  which  it  is  cov- 
ered then  effects  the  landing  of  the  instru- 
ments. 

34 


A   GLANCE  AT  THE  ATMOSPHERE 

Flying-machines,  at  the  great  ascents  of 
which  we  are  all  to-day  so  marveling,  count 
for  simply  nothing  in  explorations  of  what 
meteorologists  set  off  as  the  upper  atmosphere. 
One  has  just  now  made  a  new  world's  record  by 
reaching  a  height  of  19,650  feet,  or  a  shade  under 
three  miles  and  three-quarters.  Previous  to  this 
the  highest  flight  achieved  by  a  flying-machine 
was  18,766  feet;  and  previous  to  that  only 
16,400  feet.  Flights  to  heights  of  more  than  ten 
miles  are  a  quite  ordinary  occurrence  with  the 
balloons  sent  up  from  the  meteorological  obser- 
vatories. 

The  uppermost  or  isothermal  region  is  some- 
times regarded  as  a  mere  vaporous  cap,  lying 
sluggishly  on  top  of  the  true  atmosphere,  the 
whole  body  of  it  rising  and  falling  a  little  under 
the  disturbances  of  the  latter,  but  having, 
beyond  this,  no  appreciable  part  in  these  dis- 
turbances. It  has  presumably  no  definite  outer 
limit.  Its  likeliest  end  would  be  that  of  an  ill- 
kept  moral  resolution — simply  to  fringe  off  in 
some  perfectly  loose  manner.  It  may  at  points, 
by  a  sort  of  careless  fraying  or  flirting  out,  get 
just  beyond  reach  of  the  earth's  attraction 
and  so  lose  bits  of  itself  off  into  space.  And  it 
may  in  the  same  chance  way  gain  from  space 
35 


OUR   OWN    WEATHER 

some  bits  of  accession.  It  may,  in  its  finish, 
be  even  a  part  of  space — that  hypothetical  void 
which,  to  do  the  work  it  is  known  to  do  in  trans- 
mitting solar  energy,  absolutely  must  have  some- 
thing in  it. 


IV 

THE    CONFLICT    BETWEEN    LAND    AND    WATER 

THE  atmosphere,  it  is  evident,  has  much  to 
contend  with  in  its  own  character.  To 
adjust  the  differences  arising  simply  from  that 
would  require  a  large  amount  of  weather.  But 
the  atmosphere's  troubles  are  immensely  ag- 
gravated by  the  peculiarities  of  the  body  to 
which  it  lives  attached — our  own  curious  abode, 
the  earth.  Deriving,  as  it  does,  much  of  its 
warmth  and  coldness  directly  or  indirectly 
from  the  earth,  it  shares  in  all  of  the  earth's 
inequalities  in  generating  and  giving  off  heat. 
There  are  many  of  these,  but  by  far  the  most 
important  are  such  as  arise  from  the  natural 
difference  in  susceptibility  to  heat  that  exists 
between  land  and  water. 

No  other  substance  on  the  earth  is  so  hard  to 

heat  as  water.     It  has,  in  this  regard,  about 

twice  the  obstinacy  of  land.     This  being  the 

way  in  which  they  are  always  made,  they  offer, 

37 


OUR   OWN    WEATHER 

in  the  large  bodies  of  them  that  constitute  the 
surface  of  the  earth,  the  most  different  recep- 
tion to  the  rays  of  the  sun  that  are  transmitted 
to  them  by  the  atmosphere.  The  water  has 
only  the  smallest  friendliness  for  such  rays.  A 
considerable  number  of  them  it  wholly  refuses 
to  absorb  and  sends  them  straight  back  into  the 
atmosphere  through  which  they  came.  Or,  to 
speak  more  formally,  it  reflects  them.  Some  of 
the  rejected  ones  the  atmosphere  itself  absorbs, 
and  becomes  heated  by  them.  The  others,  pre- 
sumably, return  to  outer  space. 

Even  to  the  rays  not  definitely  sent  back 
the  water  shows  but  a  partial  receptiveness. 
Many  of  them  are  permitted  only  to  play  on 
its  outermost  surface.  They  raise  an  evapora- 
tion there,  and  in  that  may  expend  their  entire 
energy.  It  is  only  the  energy  of  such  as  manage 
to  get  deeper  in  that  produces  any  heat  in  the 
very  body  of  the  water.  Then  of  the  heat  pro- 
duced there  is  a  quick  and  generous  diffusion. 
It  passes  easily  from  particle  to  particle  by  con- 
tact; and  the  movement  natural  to  water  is 
always  bringing  cold  parts  and  warm  parts 
into  contact.  Thus  the  warmth  of  a  part 
readily  becomes,  though  in  lower  degree,  the 
warmth  of  many  parts  or  of  the  whole. 


LAND   AND   WATER   CONFLICT 

The  land  behaves  in  a  manner  almost  wholly 
the  opposite  of  this.  It  embraces  with  whole 
heart  all  the  solar  rays  that  come  to  it,  and 
quickly  acquires  heat  under  them  to  the  very 
limit  of  all  the  energy  they  bring.  It  has  little 
power  of  reflection,  and  so  it  turns  practically 
none  of  the  solar  rays  back.  It  is  incapable 
itself  of  evaporation,  and  so  it  halts  none  of 
them,  so  to  say,  at  the  door-sill.  All  that  knock 
are  let  in.  Yet  of  the  heat  into  which  the  land  is 
thrown  in  such  full  measure  by  the  visitation 
it  has  small  power  of  diffusion.  It  passes  heat 
on  but  slowly  and  with  difficulty  from  particle 
to  particle  by  simple  contact;  warm  parts 
cannot  drift  away  and  give  place  to  cold  parts, 
as  in  water;  and  so  the  heat  .in  great  measure 
adheres  to  the  portion  in  which  it  first  arose. 
Heating  so  readily  as  it  does  and  keeping  its 
heat  so  closely  within  its  own  limits,  a  given 
surface  of  land  will  show,  under  an  equal 
provocation,  two  and  three  and  even  four  times 
as  much  heat  as  a  like  surface  of  water.  And  as 
readily  as  the  land  heats  it  also  cools,  while 
the  water,  on  the  other  hand,  resigns  its  heat 
as  reluctantly  as  it  acquires  it. 

On  the  surface  of  the  earth,  one-fourth  land 
and  three-fourths  water,  this  constitutional 
39 


OUR  OWN    WEATHER 

difference  between  the  two  becomes  of  the  great- 
est consequence.  Through  the  heat  of  the  day, 
and  likewise  through  the  heat  of  the  year,  the 
seas  remain  commonly  much  cooler  than  the 
continents.  Through  the  coolness  or  coldness 
either  of  the  nights  or  of  the  year  they  remain 
much  warmer  than  the  continents.  They  warm 
less  through  the  day  or  through  the  summer  than 
the  continents  do,  and  through  the  night  or 
through  the  winter  they  cool  less.  The  differ- 
ence between  the  highest  and  the  lowest  tem- 
perature for  either  the  day  or  the  year  is  much 
less  on  sea  than  on  land. 

The  greatest  range  of  daily  temperature  occurs 
on  dry  plateaus.  In  our  own  plateau  region, 
between  the  Rocky  Mountains  and  the  Sierra 
Nevada,  the  average  difference  between  the 
highest  and  the  lowest  temperatures  of  the  day 
is  about  thirty  degrees.  In  the  parts  of  the 
country  where  it  is  least,  along  the  coasts  of 
the  Pacific  and  the  Gulf  of  Mexico,  it  is  much 
less  than  this,  but  is  still  about  eight  degrees. 
There  is,  however,  in  our  latitude  a  daily  range 
of  only  two  or  three  degrees  on  the  open  Atlantic 
Ocean.  The  average  range  of  temperature 
through  the  year  within  the  bounds  of  the 
United  States  is  in  some  places  as  much  as  sixty- 
40 


LAND  AND   WATER   CONFLICT 

five  degrees.  It  is  nowhere  less  than  thirty.  But 
on  the  surface  of  the  great  oceans,  out  far 
enough  to  escape  the  influence  of  the  land,  the 
average  difference  between  the  extremest  cold  of 
winter  and  the  extremest  heat  of  summer  is  in 
our  latitude  only  about  eighteen  degrees. 

How  Far  Down  Land  and  Sea  Warm 

Changes  of  temperature  on  the  surface  of 
the  land  show  no  effect  ordinarily  beyond  the 
depth  of  a  few  feet ;  fifty  or  sixty  feet  is  thought 
to  be  the  utmost  limit  of  them.  Below  this 
limit  temperatures  increase  rather  constantly 
with  depth,  but  show  at  any  one  point  next  to 
no  change  at  any  hour  or  season  for  that 
point.  Temperatures  of  something  over  100 
degrees,  showing  no  daily  or  yearly  variation, 
have  been  found  at  a  depth  of  four  thousand 
feet.  On  the  ocean  changes  of  surface  tem- 
perature are  effective  to  a  depth  five  or  ten 
times  greater  than  on  land.  Even  on  the 
ocean,  though,  a  great  part  is  left  undisturbed 
by  them.  The  average  depth  for  the  whole 
body  of  the  ocean  is  about  two  miles.  Down- 
ward from  the  depth  of  about  a  mile  it  has 
practically  a  constant  temperature  at  some- 
thing near  the  point  of  freezing. 


OUR   OWN    WEATHER 

Under  the  heat  of  some  record-breaking  sum- 
mer day  we  might  find  comfort — if  we  did  not 
find  only  exasperation — in  reflecting  that  at 
that  very  moment  only  a  mile  below  our  own 
level,  spread  over  three-quarters  of  the  globe,  lay 
a  blanket  a  mile  thick  and  of  a  coldness  only  a 
shade  less  than  that  of  ice;  and  that  at  the 
same  time,  some  two  or  three  miles  above  us, 
lay  enveloping  the  whole  globe  another  blanket 
fifty  or  sixty,  perhaps  seventy  or  eighty,  times 
thicker  than  the  under  one  and  of  a  coldness 
far  exceeding  that  of  ice.  At  least  it  would 
define  to  us  on  what  an  extremely  narrow  stage 
the  heat  that  to  our  feeling  so  nearly  for  the 
moment  filled  the  universe  really  played  its 
part. 

The  greater  cloudiness  of  the  atmosphere 
over  the  ocean  than  over  the  land  tends  to 
increase  the  difference  between  them  in  tem- 
perature. Clouds  shut  out  solar  radiation  and 
shut  in  radiation  from  the  earth.  Under  them 
a  surface,  whether  of  land  or  of  water,  heats 
less  and  cools  less.  The  greater  dustiness  of  the 
air  over  the  land  than  over  the  ocean  tends,  on 
the  other  hand,  to  diminish  their  difference  of 
temperature.  Dust  is  itself  absorbent  of  radia- 
tion, whether  from  the  sun  or  from  the  earth, 
42 


LAND  AND   WATER   CONFLICT 

and  so  of  any  surface  under  it  rather  retards 
the  heating  and  hastens  the  cooling. 

Viewed  simply  with  reference  to  their  effect 
on  surface  temperatures,  dust  and  clouds  might 
be  regarded  as  minor  elements  which  in  a 
measure  offset  each  other.  But  they  are  so 
variable  and  introduce  into  the  atmosphere  it- 
self such  confusion  that  they  add  greatly  to  the 
complexity  of  the  weather.  For  it  is,  finally, 
only  as  a  thing  affects  the  atmosphere  that  it 
can  have  any  importance  in  the  weather. 
Even  as  fundamental  a  matter  as  that  of  the 
sharp  division  between  land  and  water  in  their 
surface  temperatures  would  have  no  effect  on 
the  weather  if  it  were  not  a  division  shared 
by  the  air  above  them. 

It  is  in  our  own  latitude — in  the  temperate 
zone  of  the  northern  hemisphere — where  great 
continents  and  great  oceans  are  most  closely 
intermingled,  that  the  division  is  widest  and 
productive  of  its  greatest  effects.  It  occasions 
here  a  circulation  of  air  between  land  and  ocean 
as  constant  and  at  times  and  places  often  quite 
as  dominating  as  the  great  fundamental  circula- 
tion between  the  equator  and  the  poles.  Be- 
coming disproportionately  heated  in  the  sum- 
mer, and  especially  in  the  heated  part  of  the 
4  43 


OUR    OWN    WEATHER 

summer  day,  the  air  over  the  land  gets  pushed 
in  upon  at  the  surface  and  forced  upward 
by  the  cooler  air  from  the  sea.  The  lower 
winds  are  then  prevailingly  from  the  sea  to  the 
land.  In  winter  the  air  over  the  sea,  remain- 
ing unduly  warm,  is  invaded  and  driven  up- 
ward by  air  from  the  land  and  the  lower  winds 
are  prevailingly  from  the  land  to  the  sea.  The 
differences  are  much  sharper  in  winter  than  in 
summer,  and  the  winds  correspondingly  stronger. 

Permanent  Hot  and  Cold  Piles  in  the  Atmosphere 

Inasmuch  as  the  two  circulations,  that  be- 
tween land  and  sea  and  that  between  the  equator 
and  the  poles,  must  be  continually  skirting  and 
crossing  and  overleaping  and  underrunning 
and  often  violently  combating  each  other,  and 
since  they  are  both  subject  to  deflection  under 
the  overruling  force  of  the  earth's  rotation,  we 
might  expect  them  to  produce  between  them 
a  confusion  in  which  the  wit  of  mere  man  could 
discover  nothing  definite  or  calculable.  And 
certainly  the  result  does  in  no  mean  degree  con- 
form to  expectation.  Nevertheless,  out  of  all 
the  beating  and  tossing  and  whirl  there  is 
finally  threshed  a  state  of  things  clear  and  en- 
during enough  to  be  quite  counted  on.  In 
44 


LAND    AND    WATER    CONFLICT 

winter  over  the  center  of  the  great  northern 
continents  the  air  accumulates  much  as  in  the 
same  regions  ice  and  snow  accumulate  in  great 
areas  or  piles,  becoming  extremely  cold  and  dry. 
These  piles  remain  until  they  are  gradually 
thawed  away,  so  to  say,  by  the  advance  of 
summer.  Because  of  their  partial  durability 
and  because  of  the  superior  weight  they  show 
in  comparison  with  columns  of  air  in  outlying 
regions,  they  have  come  to  be  known  as  "the 
permanent  areas  of  high  pressure,"  or,  more 
briefly,  as  "the  permanent  highs." 

Over  the  north  Atlantic  and  the  north 
Pacific  are  formed,  at  the  same  time,  large, 
shallow  areas  comparatively  moist  and  warm. 
These,  too,  keep  their  place  and  character 
through  a  considerable  time,  dissipating  but 
slowly  under  the  progress  from  winter  to 
summer.  They  are  known  as  "the  perma- 
nent areas  of  low  pressure."  The  full  estab- 
lishment of  summer  sees  the  situation  exact- 
ly reversed.  Over  the  northern  Pacific  and 
the  northern  Atlantic  now  are  permanent 
highs,  and  over  the  northern  continents  are 
permanent  lows.  The  summer  continental 
lows,  however,  are  seemingly  not  so  well  de- 
fined as  the  summer  oceanic  highs. 
45 


OUR   OWN    WEATHER 

While  these  great  areas  keep  themselves 
enough  in  character  and  shape  to  have  gotten 
the  name  of  permanent,  it  is  not  to  be  in- 
ferred that  they  are  passive  or  inert.  They 
are  known  also  as  "the  great  centers  of 
action."  They  have  an  intimate  connec- 
tion with  those  smaller,  briefer,  but  still 
curiously  persistent  highs  and  lows  which, 
in  their  busy  succession,  give  form  more  or 
less  to  the  daily  household  weather  in  all 
northern  countries,  though  nowhere  else  so 
conspicuously  and  decisively  as  here  in  the 
United  States. 

Of  the  nature  and  manner  of  this  connec- 
tion the  meteorologists  know  as  yet  much  less 
than  they  wish  they  did.  There  is  no  matter 
of  which  they  are  at  the  present  moment  in 
heartier  endeavor  to  learn  more.  When  of 
this  one  thing  they  have  learned  more,  the 
mystery  of  the  weather,  it  is  believed,  will  be 
much  lessened,  and  the  art  of  weather  pre- 
diction will  acquire  an  extent  and  exactness 
considerably  beyond  the  best  it  is  as  yet 
capable  of. 

Besides  the  differences  between  land  and 
water,  very  important  in  making  up  the 
weather,  especially  in  its  more  local  mani- 
46 


LAND   AND  WATER   CONFLICT 

festations,  are  the  differences  in  the  land 
itself.  Flat  lands  acquire,  in  a  like  location, 
more  heat  than  broken  lands,  because  the 
sun  shines  upon  them  more  directly.  High 
lands  acquire,  when  of  about  the  same  even- 
ness and  location,  more  heat  than  low  lands, 
because  the  higher  they  lie  the  more  the  air 
over  them  tends  to  be  free  from  dust  and 
vapor,  and  so  to  allow  free  passage  to  the 
sunshine.  Dry  land  and  bare  land  acquire 
relatively  more  heat  than  do  wet  land  and 
land  covered  with  vegetation,  both  moisture 
and  vegetation  on  the  land  impeding  radia- 
tion just  as  vapor  in  the  atmosphere  im- 
pedes it. 

The  air  on  high  mountain  peaks  is  usually 
cold,  because  the  sunshine  is  apt  to  fall  on 
such  peaks  very  unevenly,  because  the  winds 
keep  the  air  in  constant  change,  and  because 
the  air  there,  being  freer  from  vapor  and  dust 
than  the  air  at  lower  levels,  absorbs  into  itself 
very  little  of  the  radiation  from  either  the 
sun  or  the  ground.  Over  high  plateaus  the  air 
is  apt  to  show  in  temperature  a  large  daily 
range,  becoming  very  hot  for  a  little  while 
in  the  day  and  then  very  cold.  Always 
where  there  is  rapid  heating  there  is  apt  to 
47 


OUR   OWN    WEATHER 

be  also  rapid  cooling.  Most  of  the  moisture 
of  the  land  comes  to  it  from  the  sea  under 
the  transport  of  the  atmosphere.  The  in- 
teriors of  the  large  bodies  tend,  therefore, 
to  be  dryer  than  the  borders. 

The  very  multiplicity  of  the  land's  uneven- 
nesses  tends  to  lessen  the  extent  of  the  in- 
fluence of  any  one  of  them  on  the  weather. 
They  all,  though,  give  it  a  turn  of  their  own, 
more  or  less  effective  within  the  limits  of 
their  own  several  regions;  and  the  larger 
ones,  such  as  great  mountain  ranges  and 
great  plains,  tell  a  story  of  wide  significance. 


THE    BODY    THAT    GATHERS    IN    THE    AIR     AND 
MAKES    THICK    WEATHER 

IN  all  that  makes  the  weather  truly  nourish 
— that  gives  it  vigor  and  versatility  and 
the  sharp  and  never-failing  interest  of  an  in- 
tricate variety — no  country  in  the  world  is 
richer  than  the  United  States.  The  temper- 
ate zones — "temperate"  only  in  the  fact  of 
being  less  cold  than  the  arctic  and  less  hot 
than  the  torrid  regions — are  the  parts  of  the 
earth  where  the  fundamental  circulation  of 
the  atmosphere  between  the  equator  and  the 
poles  develops  in  its  exchanging  currents 
its  sharpest  differences  of  temperature,  and 
also  where  it  suffers  its  greatest  deflections 
under  the  earth's  daily  rotation.  In  the  north 
temperate  zone,  where  land  and  water  most 
sharply  divide  the  earth  between  them,  the 
atmospheric  circulation  between  continent 
and  ocean  attains  its  greatest  force  and  per- 
49 


OUR   OWN    WEATHER 

manence.  The  United  States  may  be  re- 
garded, therefore,  as  seated  at  the  very 
center  of  the  atmospheric  conflict.  And 
seated  there,  they  offer  in  their  own  conform- 
ation about  all  that  any  land  can  to  compli- 
cate and  intensify  it. 

In  their  north  and  south  extent  of  sixteen 
hundred  miles  they  cover  about  twenty-four  de- 
grees of  latitude .  It  is  a  sufficient  length  to  give 
in  summer  two  hours  a  day  more  of  sunlight 
on  the  northern  than  on  the  southern  border. 
In  their  east  and  west  extent  of  twenty-seven 
hundred  miles  they  cover  about  fifty -eight 
degrees  of  longitude.  The  sun  rises  three 
hours  and  a  quarter  earlier  on  the  eastern 
than  on  the  western  border.  Much  the 
greatest  of  all  the  oceans,  the  Pacific,  bounds 
them  completely  on  the  west,  and  the  second 
greatest,  the  Atlantic,  on  the  east.  An  arm 
of  the  Atlantic,  the  Gulf  of  Mexico,  worthy 
itself  to  be  called,  if  not  an  ocean,  at  least  a 
sea,  washes  about  half  of  the  southern  bor- 
der, while  of  the  northern  as  large  a  part  is 
washed  by  the  Great  Lakes,  nearly  if  not 
quite  the  largest  bodies  of  fresh-water  on 
the  globe. 

The  western  third  of  the  country  is  occupied 
So 


THICK   WEATHER 

by  one  of  the  greatest  mountain  systems  in  the 
world.  In  its  two  main  ranges,  the  Rocky 
Mountains  and  the  Sierra  Nevadas,  with  the 
continuation  of  the  Sierras,  the  Cascades,  the 
system  traverses  the  entire  length  of  the 
country  and  has  at  the  widest  part  a  breadth  of 
a  thousand  miles.  Great  areas  in  this  region 
lie  at  average  elevations  of  anywhere  from 
three  thousand  to  ten  thousand  feet,  while  of 
peaks  of  a  height  of  from  twelve  thousand  feet 
to  that  of  the  highest  (Mt.  Whitney,  14,515 
feet)  there  are  literally  hundreds.  In  the 
state  of  Colorado  alone  there  are  said  to  be 
more  than  two  hundred  and  fifty  peaks  of  an 
altitude  of  more  than  thirteen  thousand  feet. 

Ridging  the  country  almost  its  entire  length 
in  the  eastern  third  is  the  Appalachian  system: 
a  rather  modest  affair  in  comparison  with  the 
Rocky  Mountain  system,  but  still  sufficient  to 
make  its  projection  often  felt  in  the  atmosphere 
and  so  on  the  weather.  Between  the  two,  run- 
ning the  entire  length  of  the  country,  and  of 
an  average  breadth  of  about  one  thousand 
miles,  is  a  region  mainly  of  plain  and  prairie, 
of  an  average  elevation  of  less  than  seven  hun- 
dred feet,  and  with  little  more  than  a  thousand 
feet  of  difference  between  its  lowest  point  and 
51 


OUR   OWN    WEATHER 

its  highest  point,  and  watered  by  one  of  the 
greatest  river  systems  in  the  world. 

If  with  such  an  extraordinary  equipment  the 
United  States  did  not  show  the  world  something 
rather  magnificent  in  the  way  of  weather  it 
would  be  a  great  reproach.  But  they  easily  save 
their  credit  in  the  matter.  Their  weather  is  all 
that  it  ought  to  be.  It  is  as  manifold  and  as 
locally  self-assertive  and  home-governed  as  the 
states  themselves,  and  it  is,  like  them,  also 
nationally  instituted  and  holds  itself  all  together 
in  a  majestic  overrule. 

The  Setting  Up  of  a  Cyclone 

Under  the  fundamental  general  movements 
and  exchanges  of  air  there  arises  in  the  western 
part  of  the  country,  or  more  often  comes  into 
it  from  the  Pacific  Ocean  or  from  northwestern 
Canada,  a  body  of  air  less  packed  together,  less 
condensed,  and  so  less  bound  to  the  earth  by 
gravity  than  the  normal.  The  normal  is  air 
that,  by  the  weight  or  pressure  of  a  column  of 
it  resting  on  the  cup  of  a  barometer,  raises  the 
mercury  in  the  tube  of  the  barometer  to  the 
height  of  thirty  inches. 

This  height,  however,  does  not  represent  the 
52 


THICK   WEATHER 

same  actual  pressure  at  all  places,  because  the 
force  of  gravity  itself  varies  from  place  to  place, 
increasing  from  the  equator  to  the  poles,  but 
diminishing  with  an  increase  of  elevation.  For 
a  standard,  therefore,  a  pressure  of  thirty 
inches  at  sea -level  in  latitude  45°  has  been 
adopted.  Commonly,  for  convenience,  all  ba- 
rometer records  are  reduced  to  this  by  simple 
calculation  before  they  are  reported.  Any 
pressure  of  more  than  thirty  inches  is  high,  and 
any  of  less  than  thirty  inches  is  low.  The 
range  under  this  gradation  is  small.  Only 
seldom  in  the  United  States  does  there  appear  a 
pressure  below  28.9  inches  or  one  above  30.7 
inches.  One  of  the  lowest  ever  reported  officially 
is  28.48  inches,  the  central  pressure  in  the  great 
Galveston  storm  of  1900.  Of  high  pressures, 
one  of  31.21  inches  reported  from  Montana  is 
perhaps  the  highest. 

A  body  of  air  of  the  kind  here  spoken  of  is 
apt  to  show,  at  its  first  appearance  within  our 
borders,  a  central  pressure  of  about  29.7  inches. 
Always  from  the  center  outward  the  pressure 
increases ;  and  the  increase  occurs  with  some- 
thing like  evenness  on  all  sides.  This  charac- 
teristic has  made  it  possible  to  chart  the 
organization  in  what  is  familiar  to  us  all  as  the 
53 


OUR   OWN    WEATHER 

daily  weather  map.  Lines  are  drawn  through 
all  the  points  of  observation  where  the  pressure 
is  shown  to  be  the  same.  The  lines  become,  in 
most  cases,  something  like  complete  circles,  and 
the  affair  appears  on  the  chart  as  a  series  of 
them,  separated  from  each  other  by  varying 
spaces,  but  all  curving  round  a  common  center. 
Sometimes  the  lines  do  not  quite  join  ends  and 
show  as  circles,  or  circular  figures,  with  a  break 
in  them.  In  that  case  the  organization  is  only 
a  weak  or  half-developed  one. 

Having  arrived,  or  arisen,  the  body  of  dif- 
fused air  comes  along  as  a  part  of  the  constant 
general  movement  eastward  of  the  main  body  of 
the  atmosphere  in  the  middle  latitudes  of  the 
northern  hemisphere.  But  if  it  becomes  well 
defined  in  its  quality  from  the  air  all  around  it, 
it  develops  in  itself  a  movement  of  its  own. 
The  effort  of  the  denser  air  around  it  to  thrust 
into  it  and  share  in  its  less  stringent  conditions 
sets  up  in  it  a  rotation  or  whirl,  and  this,  its 
own  peculiar  movement,  gives  it  a  name — that 
of  "cyclone." 

The  inflowing  currents,  under  the  force  of  the 
earth's  rotation,  are  carried  somewhat  to  the 
right  of  the  point  toward  which  they  are  striv- 
ing. Then  in  their  haste  they  somewhat  over- 
54 


THICK   WEATHER 

run  their  goal;  and,  since  the  goal  is  practically 
one  and  the  same  for  all,  they  become  more  or 
less  obstructive  and  deflective  of  each  other. 
The  total  conflict  gets  partially  compromised 
by  their  all  falling  into  a  circuit  about  the 
point  which  they  are  still  all  eager  to  reach. 
The  very  force  of  their  efforts  to  reach  it  still 
keeps  it,  though,  continually  unattainable. 
Only  defeat,  as  usual,  rewards  over-striving. 
The,  difference  of  density  between  the  inner  air 
and  the  outer,  in  which  the  whole  affair  began, 
gives  the  inner  currents  a  turn  upward  and 
the  outer  ones  a  turn  downward.  The  inner  air 
is  thus  unceasingly  carried  aloft.  A  superior 
roominess — a  space  of  disproportionately  low 
pressure — still  abides  at  the  center.  The  outer 
air  still  yields  with  energy  to  the  attraction  of 
this.  Once  well  begun,  the  chase  thus  becomes 
one  that  cannot  of  itself  end.  By  so  much  as 
the  outer  air  is  drawn  down  and  inward  the 
inner  air  is  driven  up  and  out,  and  by  so  much 
as  the  inner  air  departs  the  outer  air  seeks  to 
enter. 

The  locality  of  the  occurrence,  meanwhile, 

is  always  changing.     The  air  involved  becomes, 

in  consequence,   all  the  time  a  different  air. 

Of  the  whole  body  and  business  the  only  con- 

55 


OUR   OWN    WEATHER 

slant  part  might  seem  to  be  the  center,  which 
is  in  itself  little  more  than  a  state  or  condition. 
Thus  the  aspect  of  it  all  is  as  if  a  mere  nothing 
had  sprung  up  and  gone  stalking  about  and  had 
set  all  the  world  by  the  ears,  as,  indeed,  a  mere 
nothing  has  shown  before  now  an  ability  to  do. 
For  days  the  disturbance  goes  on  and  without 
any  change  in  its  essential  constitution,  and 
with  increase  rather  than  decrease  in  its  in- 
tensity. And  all  the  time  it  is  traveling. 
Commonly  it  traverses  the  whole  United  States 
east  of  the  point  of  its  origin  and  part  of  the 
Atlantic  Ocean,  and  sometimes  also  the  whole 
width  of  the  Atlantic  and  even  some  part  of 
the  eastern  continent,  before  it  encounters  con- 
ditions sufficiently  different  from  those  out  of 
which  it  arose  to  dissipate  and  destroy  it. 

The  Difference  between  a  Cyclone  and  a  Tornado 

The  meteorologists  are  always  at  pains  to 
warn  us  not  to  confuse,  as  in  ordinary  speech 
we  commonly  do,  the  cyclone  with  the  tornado. 
The  tornado  is  like  the  cyclone  in  that  it  is  a 
body  of  air  in  definite  whirl  about  a  center. 
But  if  measured  simply  by  its  size  it  shows  in 
comparison  with  the  cyclone  as  only  a  minute 
56 


THICK   WEATHER 

affair.  It  has,  though,  in  proportion  to  its 
size  an  extraordinary  capacity  for  business.  It 
tears  things  to  pieces  and  destroys  life  with 
a  greediness  that  makes  it  justly  a  terror  in  the 
regions  which  it  infests. 

The  cyclone,  on  the  contrary,  is  not  apt  to 
be  in  itself  violent.  It  spreads  itself  out  in  a 
large  indifferent  way,  as  if,  while  meaning  to* 
possess  whatever  territory  it  found  attractive, 
it  were  too  majestic  and  careless  to  pillage  or 
destroy.  But,  like  some  other  majesties,  it 
often  carries  in  its  train  creatures  of  a  smaller 
and  maligner  nature.  Of  these,  the  tornado  is 
one,  and  the  worst.  It  is  a  mere  hanger-on  and 
dependent  of  the  cyclone.  It  lives  and  works 
only  under  the  cyclone's  allowance.  It  springs 
up  suddenly  and  runs  its  course  with  great  swift- 
ness, and  this  is  what  makes  it  so  destructive. 
There  is  never  any  but  the  briefest  warning  of 
it,  and  its  passage  suggests  the  lightning,  which 
is  gone  before  one  can  say  it  lightens. 

The  cyclone,  on  the  other  hand,  often  forms 
slowly.  The  Weather  Bureau  may  have  had 
it  under  observation  for  a  day  or  two  before 
feeling  justified  in  pronouncing  it  a  cyclone. 
After  it  has  in  a  measure  declared  itself  it 
usually  comes  along  at  considerable  speed; 
57 


OUR   OWN    WEATHER 

but  it  is  like  other  large  and  deliberate  bodies, 
and  does  not  care  always  to  hurry.  As  if  in 
mere  self-indulgence,  it  sometimes  loiters  on  the 
way,  withholding  the  activity  it  is  all  the  time 
promising  and  keeping  weather  forecasters  and 
whole  states  and  thousands  of  people  waiting 
for  it. 

The  Size  and  Frequency  of  Cyclones 

The  extent  of  a  cyclone  is  often  marvelous. 
There  is  a  wide  variation  from  cyclone  to  cy- 
clone, but  the  average  extent  has  been  calcu- 
lated to  be  some  three  hundred  thousand  square 
miles.  This  is  an  area  about  equal  to  that  of 
Kansas,  Nebraska,  Iowa,  and  Missouri,  with  a 
third  of  Illinois  added.  Some  cyclones  are  not 
so  large  as  this,  but  some  are  very  much 
larger.  Often  a  single  one  is  the  dominating 
influence  in  the  lower  air  all  the  way  from  the 
foot  of  the  Rocky  Mountains  to  the  Atlantic 
Ocean  and  from  Canada  to  the  Gulf  of  Mexico. 

So  immensely  spread  out  and  so  impalpable 
as  the  cyclone  is,  we  can  scarcely  apprehend  it  as 
a  strict  material  body,  held  within  its  own 
bounds,  active  in  functions  purely  its  own,  and 
capable  of  transportation  from  place  to  place 
in  the  general  atmospheric  movement  without 
58 


THICK   WEATHER 

loss  of  its  individuality.  But  this,  none  the 
less,  is  what  it  is.  The  deep-set,  towering 
mountains  over  which,  oftener  than  not,  we 
first  discover  it  are  not  more  real,  and  give,  in 
fact,  less  evidence  of  definite,  direct  power  and 
activity. 

These  areas  of  air  of  abnormally  low  pressure 
are  crossing  the  country  from  the  Pacific 
Ocean  to  the  Atlantic  in  a  fairly  close  and  even 
procession  the  whole  year  through.  They  are 
more  numerous  from  the  beginning  of  October 
to  the  beginning  of  April  than  they  are  from 
the  beginning  of  April  to  the  beginning  of 
October.  The  month  in  which  they  are  apt  to 
be  fewest  is  June.  But  even  in  June  there  are, 
on  an  average,  no  fewer  than  eight,  or  one  every 
three  or  four  days ;  and  in  December,  January, 
February,  or  March,  in  either  one  of  which 
they  may  happen  to  be  most  frequent,  there 
are  generally  never  more  than  eleven  or  twelve. 
They  take  from  three  to  five  days  for  their 
journey  across  the  country.  One  can,  there- 
fore, practically  never  look  at  the  daily  weather 
map  without  seeing  printed  somewhere  there 
in  bold  black  type  the  word  "Low,"  which  is  the 
word  always  used  to  designate  the  areas  of  low 
pressure  in  charting  their  locations  and  progress. 
5  59 


OUR   OWN    WEATHER 

All  the  areas  of  low  pressure  that  cross  the 
whole  or  a  good  part  of  the  country  do  not 
organize  into  complete  and  perfect  cyclones. 
But  they  all  have  much  of  the  fundamental 
character  of  the  cyclone.  They  are  all,  because 
of  their  low  pressure,  their  expansion,  drawing 
in  air  from  surrounding  regions  and  more  or 
less  discharging  it  aloft.  They  all  remain  for 
at  least  some  days  fairly  well  marked,  and  they 
maintain  during  such  time  a  fairly  continuous 
progress  eastward.  They  all  make  and  unmake 
the  weather  of  the  localities  over  which  they 
pass,  varying  in  this  from  one  another  only  in 
their  vigor.  It  is  merely  their  vigor  that  de- 
termines for  them  whether  they  shall  have  what 
is  in  strictness  the  distinguishing  cyclonic  fea- 
ture— namely,  a  continuing  internal  whirl.  Only 
the  more  intense  ones  develop  the  whirl. 

The  whirl  of  a  cyclone  is  always  in  what,  to 
a  person  placed  at  the  center  of  it,  would  be 
from  right  to  left,  or,  as  expositors  of  the  sub- 
ject usually  add,  in  order  to  make  the  thing  more 
memorable  to  us,  in  a  direction  contrary  to  that 
of  the  movement  of  the  hands  of  a  clock. 
This  is  its  direction  anywhere  in  the  northern 
hemisphere;  but  since  the  direction  is  dictated 
by  the  rotation  of  the  earth,  it  would  anywhere 
60 


THICK    WEATHER 

in  the  southern  hemisphere  be  just  the  other 
way.  In  some  instances  the  whirl  becomes 
rapid,  but  it  is  not  ordinarily  so.  At  the  center 
is  a  region  of  calm,  but  it  is  never  the  clearly 
denned,  emphatic,  ominous  calm  that  lends 
such  picturesqueness  to  the  descriptions  of 
ocean  hurricanes.  The  passage  of  the  center 
over  a  locality  does  little  more  than  produce  in  a 
prevailing  storm  a  slight  halt  or  lull. 

The  Form  and  the  Qualities  of  a  Cyclone 

In  form  a  cyclone  is  never  exactly  a  circle. 
Usually  it  is  a  not  very  regular  ellipse  and  shows 
a  length  oftenest  about  double,  but  occasion- 
ally as  much  as  four  times,  its  greatest  width. 
When  it  first  appears  in  the  Far  West  it  is  apt 
to  have  its  length  from  northwest  to  southeast, 
but  as  it  moves  eastward  it  shifts  its  form  and 
becomes  longest  from  northeast  to  southwest. 
Its  greatest  length  may  be  not  more  than  three 
or  four  hundred  miles,  but  is  sometimes  as 
much  as  sixteen  hundred,  or  the  equivalent  of 
the  distance  in  a  straight  line  from  Texas  to 
Maine. 

Mathematically,  an  ellipse  is  rather  permitted 
to  have  two  centers,  and  sometimes  a  cyclone 
61 


OUR   OWN    WEATHER 

has  two.  But  it  becomes  in  such  a  case  so 
lengthened  out  and  of  such  crude  form  that  it  is 
usually  called  a  trough.  "A  trough  of  low 
pressure"  is  a  phrase  familiar  to  readers  of  the 
daily  weather  reports,  and  none  too  grateful 
to  them,  since  it  is  likely  to  betoken  a  period  of 
sluggish  bad  weather.  Usually  in  the  forma- 
tion of  a  trough  a  center  of  low  pressure  up 
about  the  Great  Lakes  has  entered  into  a  kind  of 
trust  with  one  down  in  the  neighborhood  of  the 
Gulf,  and  the  combination  holds  ground  in  a 
rather  dull,  obstructive  way,  northeast  and 
southwest,  over  the  lower  Mississippi  and  Ohio 
valleys,  a  business  without,  for  the  moment, 
any  real  head.  Quite  often,  though,  after 
loitering  inefficiently  for  a  day  or  two,  a  trough 
suddenly  pulls  itself  together  and  becomes  an 
organization  of  real  form  and  depth  and  vigor. 
Some  of  the  strongest  storms  experienced  in 
the  Mississippi  valley  and  eastward  are  of  this 
character. 

A  cyclone  owes  its  life  and  energy  first  and 
last  solely  to  disparities  of  temperature.  But 
it  is  not  an  area  of  air  of  evenly  warm  tempera- 
ture, ringed  in  all  around  by  air  of  an  evenly 
low  temperature.  If  it  were  that,  it  might  be 
easier  to  figure  out  and  explain  than  it  actually 
62 


THICK    WEATHER 

is.  The  air  flowing  into  it  from  the  north  and 
west  is  colder,  denser,  and  so  of  greater  force 
than  the  air  flowing  into  it  from  the  south  and 
east.  Therefore,  of  the  winds  it  raises  those 
from  the  northwest  are  the  strongest.  Next  in 
strength  are  those  from  the  southeast,  then 
those  from  the  southwest,  and  then  those  from 
the  northeast. 

A  fair  illustration  of  the  matter  is  furnished 
by  a  winter  cyclone  (winter  cyclones  show 
stronger,  as  a  rule,  in  all  features  than  summer 
cyclones)  that,  while  central  near  the  mouth  of 
the  Ohio  River,  produced  surface  winds  of  from 
eight  to  twelve  miles  an  hour  in  its  central 
region  and  of  from  twenty  to  thirty-eight  miles 
an  hour  in  its  northwest,  from  eighteen  to 
thirty  in  its  southeast,  from  eighteen  to  twenty 
in  its  southwest,  and  from  twelve  to  sixteen 
in  its  northeast  region.  On  all  sides  the  winds 
increase  in  strength  as  they  near  the  central 
area  of  the  cyclone.  Low  down  they  are  locally 
more  or  less  affected,  though,  in  both  their 
direction  and  their  force  by  the  irregularities 
of  the  ground. 

The  cyclone  reproduces  in  its  own  temper- 
ature the  difference  of  warmth  in  the  vari- 
ous invasions  which  it  suffers.  In  the  region 
63 


OUR   OWN    WEATHER 

covered  by  its  northwest  quarter  the  aver- 
age temperature  will  be  much  lower  than  in  that 
covered  by  any  of  its  other  quarters.  In  the 
region  covered  by  its  southeast  quarter,  on  the 
other  hand,  the  average  temperature  will  be 
much  higher  than  in  any  covered  by  other 
quarters. 

Up  to  a  considerable  height  the  cyclone  re- 
tains unimpaired  all  of  the  characteristics  that 
mark  it  below.  It  still  shows  a  clear  flowing  in 
of  air  from  all  sides  and  upward  from  the 
center.  The  temperatures  lower  quite  regu- 
larly with  every  increase  of  altitude,  and  the  air 
becomes  in  all  quarters  colder;  but  the  dis- 
tribution of  temperatures  among  the  several 
quarters  remains  about  the  same.  The  winds 
all  increase  greatly  in  strength,  becoming  at  the 
height  of  two  miles  from  two  to  three  times  as 
strong  as  they  were  at  the  ground.  At  that 
height,  though,  or  even  somewhat  below  it,  the 
winds  from  the  west  begin  to  show  much  the 
greater  increase,  and  from  there  upward  the 
traces  of  winds  from  the  east  grow  fainter  and 
fainter,  until  finally  the  whole  organization 
becomes  blurred  and  then  blotted  out  in  the 
permanent  flow  of  the  general  atmosphere  from 
west  to  east. 

64 


THICK   WEATHER 

Three  miles,  or  at  most  four,  is  now  rated 
to  be  about  the  full  upward  limit  of  American 
cyclones.  At  that  height  they  become  absorbed 
in  the  constant  eastward  flow  of  the  general  at- 
mosphere, and,  while  they  may  there  somewhat 
retard  or  deflect  that  flow,  they  retain  no  longer 
their  own  characteristic  flow  upward.  This 
causes  them  to  be  accounted  shallow  disturb- 
ances, and  leaves  them,  as  regards  size,  pre- 
eminent only  in  their  area,  or  horizontal  ex- 
tension. The  European  cyclone,  which  in  com- 
parison with  the  American  is  regarded  as  not 
much  of  an  affair,  has,  in  general,  a  height  of 
something  over  five  miles,  and  the  tropical 
hurricane,  also  a  cyclone,  though  of  a  somewhat 
different  order  from  the  temperate-zone  cy- 
clones, and  of  not  more  than  one-third  the 
breadth  of  the  American  cyclone,  shows  some- 
times a  height  of  more  than  six  miles. 

In  view  of  the  immense  extent  and  long  per- 
sistence of  the  American  cyclone,  its  shallowness 
adds  greatly  to  its  strangeness.  The  question 
asked  in  effect  by  Dr.  Hann,  the  eminent 
Austrian  meteorologist,  how  such  a  "paper- 
thin"  and  so  spread-out  (eine  derart  papierdinne 
aber  so  ausgedehnte)  air  area  can  so  perfectly  and 
for  so  long  maintain  itself  is  the  question  asked 
65 


OUR   OWN    WEATHER 

by  all  meteorologists.  The  answers  they  have 
thus  far  given  to  it  are  not,  it  must  be  said,  as 
full  and  clear  as  could  be  desired.  They  them- 
selves acknowledge  in  the  matter  a  mystery 
which  they  have  not  yet  entirely  resolved. 


VI 


HOW  THE  STORM  BODIES  TRAVEL  AND  DO  THEIR 
WORK 

OF  the  hundred  and  ten  or  twenty  areas  of 
air  of  low  pressure  that  come  into  clear 
existence  and  traverse  a  considerable  portion 
of  the  country  in  the  course  of  a  year  as  many 
as  forty  come  in  across  the  northern  border  of 
Montana  from  the  Canadian  province  of 
Alberta.  About  twenty  come  in  straight  along 
the  northern  border  of  the  country  from  the 
north  Pacific  Ocean.  Some  nine  or  ten  first 
declare  themselves  over  the  north  Rocky 
Mountain  plateau,  and  twelve  or  thirteen  some- 
where in  Colorado.  Thus  quite  two-thirds  of 
the  whole  number  arise  or  first  appear  in  the 
extreme  northwest  quarter  of  the  country.  Of 
the  other  third  from  twelve  to  fifteen  are  south- 
western in  their  origin,  two  or  three  a  year 
coming  in  from  the  south  Pacific  coast  and  ten 
or  twelve  arising  in  Texas.  Six  or  seven  are 
67 


OUR   OWN    WEATHER 

apt  to  spring  up  in  the  east  Gulf  and  south 
Atlantic  region,  and  a  like  number  in  the  region 
of  the  mouth  of  the  Ohio  River. 

In  much  the  larger  number  of  instances  it  is, 
therefore,  from  somewhere  along  the  line  of  the 
Rocky  Mountains  that  our  cyclone  begins  its 
visible  course.  Wherever  it  sets  out  it  betrays 
always  a  clear  desire  to  travel  into  the  valley 
of  the  St.  Lawrence  River  and  thence  out  to 
sea.  Most  times  it  wholly  succeeds  in  this 
desire,  and  a  consequence  is  that  "the  valley 
of  the  St.  Lawrence,"  according  to  a  statement 
of  General  Greely,  former  chief  of  the  Unit- 
ed States  Weather  Bureau,  "has  the  largest 
number  of  storms  of  any  section  of  the 
globe." 

Like  all  other  earthly  bodies,  though,  the 
cyclone  gets  its  way  only  by  compromise  with 
various  hindrances.  Often  it  is  permitted  to 
go  to  the  St.  Lawrence  by  the  straightest  path, 
but  about  as  often  it  is  compelled  to  make  large 
detours.  What  draws  it  toward  the  St.  Law- 
rence is  the  permanent  eastward  drift  of  the 
general  atmosphere.  This  is  thought  to  be  par- 
ticularly strong,  even,  perhaps,  at  its  very 
strongest,  in  the  latitude  of  our  northern  bor- 
der. The  cyclone,  if  under  no  other  compul- 
68 


HOW  THE  STORM  BODIES  TRAVEL 

sion,  yields  to  it  and  as  quickly  as  possible 
comes  into  line  with  it  at  the  point  and  in  the 
direction  of  its  greatest  strength. 

No  matter  whether  the  cyclone  arises  near 
the  northern  border  or  in  the  far  Southwest  or 
on  the  south  Atlantic  coast  it  still  shows  this 
overmastering  urgency  to  get  into  the  full  tide 
of  the  general  eastward  drift.  But  it  is  very 
apt  to  have  near  it  another  more  or  less  organ- 
ized body  of  air  of  exactly  the  opposite  char- 
acter. This  is  what  is  known  as  an  area  of  high 
pressure,  or  an  anticyclone — a  body  in  which 
the  air,  more  condensed  and  forceful  than  in  the 
cyclone,  is  flowing  downward  and  outward.  In 
nearly  all  cases  where  a  cyclone  departs  from 
the  straight  path  it  is  attracted  or  diverted,  the 
belief  now  is,  by  an  anticyclone. 

Even  in  its  deviations,  however,  the  cyclone 
shows  a  very  appreciable  regularity.  It  has 
been  studied  and  charted  with  the  utmost 
minuteness  in  its  various  tracks.  No  deeply 
concealed  human  fugitive  was  ever  run  down 
more  triumphantly  by  the  most  patient  and 
acute  detectives.  And  it  has  been  found  to 
depart  in  any  of  its  courses  very  little  from  one 
or  the  other  of  two  general  lines.  When  it  does 
not  travel  pretty  straightly  away  to  the  St. 
69 


OUR   OWN    WEATHER 

Lawrence  valley  it  makes  a  dip  southward  some- 
where along  the  eastern  slope  of  the  Rocky 
Mountains,  and  then,  turning,  proceeds  quite 
directly  northeastward.  And  in  its  dip  it  does 
not  stray  beyond  certain  limits.  When  it  sets 
out  from  either  Montana  or  the  north  Rocky 
Mountain  plateau  it  never  gets  farther  south 
than  northern  Kansas.  When  it  sets  out  from 
either  Colorado  or  Texas  it  makes  almost  no 
dip  at  all,  but  strikes  nearly  at  once  into  a  true 
northeast  course. 

It  gets  an  aspect  of  pure  waywardness  only 
when,  starting  on  the  north  Pacific  coast,  in  the 
state  of  Washington,  or  on  the  south  Pacific 
coast,  in  southern  California,  it  beats  southeast 
almost  straight  to  Texas  and  the  Gulf  of  Mexico. 
No  doubt,  in  such  a  case  the  immense  rugged- 
ness  of  the  country  combines  with  a  more  than 
ordinary  obstinacy  in  the  surrounding  masses  of 
air  to  drive  the  poor  cyclone  quite  mad.  But 
the  case  happens  very  rarely — not  oftener,  per- 
haps, than  two  or  three  times  in  the  course  of 
ten  years.  The  limits,  indeed,  within  which  the 
cyclone  commonly  confines  its  course  are  com- 
paratively so  strict  and  narrow  that  it  is  usu- 
ally spoken  of  as  traveling  by  either  its  northern 
or  its  southern  circuit,  the  northern  being  the 
70 


HOW  THE  STORM  BODIES  TRAVEL 

straight  and  shorter  way  and  the  southern  the 
curved  and  longer. 

Preferring  always  the  northern  circuit,  the 
cyclone  finds  itself  much  less  thwarted  in  this 
preference  through  the  summer  and  early 
autumn  than  through  the  winter  and  early 
spring.  It  is  then,  owing  to  the  wide  and 
fairly  even  spread  of  warmth  over  the  northern 
hemisphere,  less  subject  to  the  push  and  pull  of 
large,  strong  areas  of  air  of  high  pressure 
thrusting  down  from  the  cold  north.  It  is 
itself,  at  this  season,  rather  a  mild  body,  little 
inviting  conflict  or  opposition,  and  moves  along 
with  comparatively  slight  disturbance  by  the 
way  it  best  likes. 

The  Government  charts  in  which  the  cyclone's 
courses  at  different  seasons  are  all  graphically 
portrayed  show  for  midsummer  little  more  than 
a  simple  succession  of  almost  straight  lines. 
For  midwinter,  though,  the  portrayal  is  such  a 
network  of  curves  and  crossings  that  at  first 
glance  it  might  seem  to  offer  not  the  least  trace 
of  law  or  order.  A  closer  look  will  soon  clear 
it  up.  The  courses  nearly  all  loop  more  or  less 
southward;  but  they  still  keep  within  rather 
clear  bounds  and  come  finally  all  into  one  gen- 
eral direction — northeast. 


OUR   OWN    WEATHER 

The  Speed  of  Cyclones 

In  either  circuit  the  cyclone  travels  with  a 
speed  always,  closely  correspondent  to  the  de- 
gree of  its  own  perfection.  If  it  is  a  complete 
cyclone  and  of  extreme  intensity  it  may  make 
as  much  as  sixty  miles  an  hour.  But  if  it  is 
feeble  in  its  organization  it  may  not  make  more 
than  fifteen.  It  presents  itself  in  strong  form 
more  often  in  winter  than  in  summer.  It  shows, 
therefore,  a  higher  average  rate  of  speed 
through  the  winter  half  of  the  year  than  through 
the  summer  half.  For  the  latter  the  average 
rate  has  been  found  to  be  a  little  over  twenty- 
six  miles  an  hour,  and  for  the  former  a  little 
over  thirty-two. 

In  general,  a  cyclone  starting  from  Mon- 
tana, if  it  chooses  the  northern  circuit,  will  have 
come,  at  the  end  of  its  first  day's  travel,  nearly 
to  the  eastern  border  of  North  Dakota.  At  the 
end  of  the  second  day  it  will  be  centered  some- 
where over  Lake  Superior.  The  third  day  will 
carry  it  well  into  the  St.  Lawrence  valley,  and 
the  fourth  day  will  bring  it  the  Weather  Bureau's 
familiar  dismissal,  "Passed  out  to  sea."  If  it 
chooses  the  southern  circuit  and  drops  down 
into  Kansas  or  Missouri  it  will  be  a  day  longer 
72 


HOW  THE  STORM  BODIES  TRAVEL 

on  its  journey.  It  is  apt  to  show,  though, 
greater  speed  on  the  southern  circuit  than  on  the 
northern.  Starting  from  western  or  southern 
Texas,  it  often  goes  with  great  rapidity,  reaching 
the  St.  Lawrence  valley  in  three  days. 

It  may,  however,  when  traveling  by  the 
southern  circuit,  miss  that  much  preferred  re- 
gion entirely.  The  strain  of  its  deflection 
southward  may  keep  it  from  turning  back  soon 
or  sharply  enough  to  get  as  far  north  as  the  St. 
Lawrence  valley  before  it  is  carried  to  the 
Atlantic  Ocean.  It  will  still  go  on,  though,  in 
a  clear  northeast  course,  intent  as  ever  to  come 
into  line  with  the  swiftest  part  of  the  general 
upper  eastward  drift.  And  its  failures  to  reach 
at  least  some  border  of  the  St.  Lawrence  val- 
ley are,  all  told,  very  few.  For  the  last  stage 
of  the  journey  the  path  most  trodden  is  a 
line  running  about  midway  between  New  York 
City  and  Buffalo,  about  midway  between  Boston 
and  Montreal,  and  a  little  north  of  Halifax. 
People  living  along  that  line  may  boast  or 
complain  that  they  get  in  the  matter  of  weather 
about  all  that  is  to  be  had  in  the  whole  United 
States. 

While  well-formed  cyclones  almost  never 
fail  to  reach  the  Atlantic  Ocean,  only  very 
73 


OUR   OWN    WEATHER 

rarely  are  they  able  to  cross  it.  They  at  once 
lose  speed,  slowing  down  to  an  average  rate  of 
about  nineteen  miles  an  hour,  and  are  apt 
before  the  passage  ends  to  become  entirely 
blotted  out.  Of  the  few  that  do  get  across  not 
more  than  one  in  nine  touches  Great  Britain 
or  the  middle  part  of  the  western  coast  of  the 
Eastern  Continent.  The  others,  under  their 
strong  northeastward  impulse,  are  carried  to 
Iceland  and  the  coast  of  Norway  and,  if  they 
still  survive,  across  northern  Russia.  Never 
one,  it  is  affirmed,  holds  out  all  the  way  to  the 
eastern  coast  of  Asia. 

Authoritative  practice  makes  the  word  "cy- 
clone" almost  interchangeable  with  the  word 
"storm."  The  practice,  though,  does  some 
violence  to  the  associations  of  ordinary  usage. 
A  fully  formed  and  even  strong  cyclone  may 
travel  all  the  way  from  Montana  to  the  St. 
Lawrence  valley  and  produce  practically  no 
rain.  This  makes,  to  our  every-day  concep- 
tion, a  rather  empty  "storm."  To  the  meteor- 
ologist "storm"  is  almost  exclusively  a  matter 
of  wind.  But  even  in  the  raising  of  wind  the 
cyclone  may  fall  much  short  of  the  usual  idea 
of  storminess.  It  may  be  quite  able  to  travel 
and  to  draw  the  air  into  it  from  over  a  wide 
74 


HOW  THE  STORM  BODIES  TRAVEL 

area  and  still  raise  the  wind  to  nothing  more 
than  freshness — that  is  to  say,  to  a  force  of  not 
more  than  eleven  or  twelve  miles  an  hour. 
Yet  all  the  time  and  all  over  the  country,  at 
least  anywhere  east  of  the  Rocky  Mountains, 
the  winds  are  more  or  less  under  the  control  of 
the  cyclone  and  its  co-partner,  the  anti-cyclone. 
And  as  for  rain  or  its  winter  equivalent,  snow, 
there  is  east  of  the  Rocky  Mountains  never  a 
truly  great  fall  that  it  is  not  due  directly  to  the 
passage  of  a  cyclone.  Even  the  larger  number 
of  what  are  classed  as  local  rains  arise  only  out 
of  conditions  that  the  cyclone  has  made  for 
them.  The  cyclone  is  not  itself  a  traveling 
body  of  either  rain  or  wind  or  of  weather  of  any 
sort.  But  it  arouses  and  drives  along  much  the 
greater  part  of  all  that  we  commonly  have  in 
mind  when  we  speak  of  stormy  weather.  What 
it  shall  accomplish  in  this  way  will  depend  very 
much  on  what  it  encounters  in  its  progress.  Its 
grand  function  is  to  set  things  off. 

Change  in  Winds  and  Temperature  at  the 
Approach  of  a  Cyclone 

In  any  region  upon  which  a  cyclone  is  ad- 
vancing its  earliest  effect  is  likely  to  be  a  shift- 
6  75 


OUR   OWN    WEATHER 

ing  of  the  winds.  Instead  of  blowing,  as  in 
quiet  weather  they  most  commonly  do,  from 
the  northwest,  they  will  begin  to  blow  from  some 
point  between  northeast  and  south.  During  the 
day,  in  summer,  along  the  Atlantic  and  Gulf 
coasts  the  effect  might  be  less  to  alter  the  wind's 
direction  than  to  increase  its  force ;  for  there  the 
wind  during  the  day,  in  summer,  comes  usually 
from  the  sea  and  would  be  likely  to  have  already 
about  the  direction  which  the  cyclone  tends  to 
establish.  In  other  localities  as  well  some 
special  condition  might  check  or  thwart  the 
general  tendency.  But  at  most  places  any- 
where in  advance  of  the  cyclone  and  within  its 
influence  the  winds  would  be  pretty  nearly 
reversed.  And  this  effect  might  appear  as  much 
as  a  thousand  miles  away  from  the  center  of  the 
cyclone. 

As  the  center  of  the  cyclone  comes  nearer 
the  wind  increases  in  strength.  It  continues 
at  the  same  time  to  alter  its  direction,  until 
by  the  time  the  center  of  the  cyclone  has  passed 
it  will  be  coming  from  the  northwest.  Just  in 
its  first  descent  from  this  direction  it  is  likely 
to  show  itself  at  its  very  strongest;  for  it  is  in 
the  northwest  wind,  just  at  its  entrance  into  the 
central  region,  that  the  greatest  force  of  wind 
76 


HOW  THE  STORM  BODIES  TRAVEL 

anywhere  about  the  cyclone  is  usually  found. 
But  as  the  cyclone  moves  away  the  wind,  while 
continuing  from  the  northwest,  will  gradually 
diminish.  At  places  lying  in  the  upper,  or  left- 
hand,  half  of  the  cyclone's  course  and  influence 
the  wind  will  "back" — that  is,  go  by  the  north 
— into  the  northwest ;  and  at  those  lying  in  the 
lower,  or  right-hand,  half  the  wind  will ' '  veer ' ' — 
that  is,  go  by  the  south — into  the  northwest. 

Almost  simultaneously  with  the  first  shift  of 
the  wind  in  advance  of  a  cyclone  the  air  begins 
to  show  a  change  of  quality.  Before  this  has 
yet  become  apparent  to  our  feelings  it  is 
marked  by  the  barometer.  The  barometer 
begins  steadily  to  fall,  showing  that  the  air  is 
losing  weight,  or  pressure,  and,  also,  that  it  must 
be  growing  both  warmer  and  moister.  Very 
soon,  though,  the  change  begins  also  to  be  felt. 
The  weather  becomes  sensibly  warmer  and  less 
fair.  Often  a  cyclone,  while  it  is  still  centered 
somewhere  on  the  eastern  slope  of  the  Rocky 
Mountains,  will  already  have  produced  leaden 
skies  and  higher  temperatures  over  the  whole 
country  east  of  it.  It  is  apt,  though,  to  show  its 
first  effect  on  the  temperature  at  points  farther 
away  from  its  center  than  the  farthest  to  which 
it  sends  out  its  clouds. 

77 


OUR   OWN    WEATHER 

The  clouds  that  give  earliest  notice  of  it  are 
the  long,  thin,  fringy,  light  silver  clouds  fa- 
miliarly known  as  cat's-tails  or  mare's-tails, 
and  scientifically  as  cirrus.  They  have  usually 
the  look  of  being,  as  they  always  are,  cold  and 
high  up.  Air  sent  far  aloft  in  its  discharge 
from  the  center  of  the  cyclone  encounters  such 
coldness  that  its  moisture  is  condensed,  not 
into  water  particles,  but  into  particles  of  ice. 
Of  the  clouds  so  formed  parts  are  sometimes 
swept  a  little  to  the  rear  of  the  cyclone,  but  the 
main  body  is  caught  up  and  carried  eastward 
in  the  movement  of  the  general  atmosphere. 

It  is  the  same  movement  that  controls  the 
progress  of  the  cyclone.  But  the  cyclone  is 
more  or  less  turned  aside  and  held  back  through 
being  tied  at  one  end  to  the  earth.  The  cirrus 
clouds,  lying  far  above  such  retardations,  soon 
acquire  pretty  nearly  the  speed  of  the  movement 
itself.  About  all  we  know  of  that  speed  we 
learn,  indeed,  by  measuring  the  rate  of  travel 
shown  by  the  cirrus  clouds.  They  so  far  out- 
run the  cyclone  that  at  their  easternmost  ex- 
tension they  may  be  as  much  as  two  or  three 
days  ahead  of  it.  They  are  a  sure  sign  of  its 
coming.  But  they  do  not  mark  with  any  great 
exactness  within  what  time  it  will  come. 
78 


HOW  THE  STORM  BODIES  TRAVEL 

As  soon  as  bodies  of  warm,  moist  air  begin 
to  be  drawn  westward  and  northward  from  the 
east  and  the  south  they  come  into  contact  with 
bodies  somewhat  dryer  and  cooler.  With  these, 
little  by  little,  they  share  their  superior  warmth, 
and  it  is  in  this  way  that  the  general  tempera- 
ture is  raised.  But  in  the  process  their  own 
temperature  is  lowered  just  enough  to  make  the 
amount  of  moisture  they  were  originally  charged 
with  too  much  for  them  and  to  set  it  condensing 
into  clouds. 

In  advance  of  a  cyclone  clouds  of  this  kind 
may  begin  to  arise  before  the  cirrus  clouds  ap- 
pear. At  first,  though,  they  are  such  as  might 
arise  from  some  disturbance  more  temporary 
and  local  than  a  cyclone;  and  it  is  only  as  the 
cyclone  gets  comparatively  near  and  they 
spread  out  and  thicken  that  they  grow  into  a 
clear  sign  of  its  coming.  They  may,  by  their 
spreading  out  and  thickening,  check  the  ordi- 
nary daily  radiation  of  heat  from  the  earth  and 
the  lower  atmosphere,  and  thus  increase  locally 
the  rise  of  temperature  provoked  in  the  first  place 
by  the  cyclone.  This  rise  sometimes  becomes 
as  much  as  thirty  degrees  above  the  normal. 

In  both  increased  warmth  and  increased 
cloudiness  the  cyclone  becomes  locally  more 
79 


OUR   OWN    WEATHER 

manifest  as  it  gets  nearer.  As  soon  as  the 
center  of  it  has  gone  by  the  temperature  begins 
to  diminish.  The  warm  currents  from  the 
east  and  south  give  place  to  the  cold  ones  from 
the  west  and  north,  and  at  the  first  touch  of 
these  the  weather  at  any  given  place  becomes 
cooler.  But  of  cloudiness  a  cyclone  often  has 
a  considerable  extent  behind  it,  though  less 
than  before  it.  The  extent  both  before  and 
behind  varies  with  the  intensity  of  the  cyclone, 
but  amounts  on  an  average  to  a  prevailing 
cloudiness  for  from  four  hundred  to  six  hundred 
miles  on  either  side  from  the  center.  In  a  well- 
organized  cyclone,  central  over  the  lower  Ohio 
River,  there  will  be  a  pretty  complete  cloudi- 
ness from  the  upper  Lake  region  to  the  Gulf  of 
Mexico  and  from  eastern  Kansas  to  the  Atlantic 
Ocean. 

How  the  Cyclone  Produces  Rain 

The  conditions  which  produce  cloudiness  all 
about  a  cyclone  also  produce  rain  if  only  they 
are  strong  enough.  The  capacity  of  a  body 
of  air  to  carry  moisture,  or  water-vapor,  with- 
out spilling  any  is  always  in  proportion  to  its 
temperature.  Air  at  a  temperature  of  fifty-one 
degrees  can  carry  securely  twice  as  much  as  air 
80 


HOW  THE  STORM  BODIES  TRAVEL 

at  a  temperature  of  thirty- two  degrees.  When, 
as  about  a  cyclone,  warm  currents  laden  to 
nearly  their  limit  with  moisture  run  swiftly  into 
the  face  of  colder  currents  that  are,  perhaps, 
themselves,  in  proportion  to  their  temperature, 
not  overdry,  sharp  disparities  between  tem- 
perature and  moisture  are  bound  to  follow. 
They  follow  also  upon  the  rapid  cooling  of  the 
air  in  its  constant  rise  from  the  center  of  the 
cyclone  to  higher,  colder  levels. 

The  only  way  to  set  things  right  in  such  a 
case  is  through  condensation.  If  the  need  is 
not  too  strong,  condensation  simply  into  clouds, 
to  be  blown  off  and  finally  dissolved  in  areas 
of  air  that  can  accommodate  more  moisture, 
will  quite  suffice.  But  if  the  need  is  stronger, 
resort  must  be  had  to  the  extreme  remedy  of 
rain — to  a  complete,  undisguised  spill.  Very 
rarely  does  a  well-formed  cyclone  traverse  the 
country  without  somewhere  producing  rain. 
But  the  amount  it  produces  depends  not  a  little 
on  where  it  starts  and  by  what  route  it  travels. 

In  northern  Montana,  east  of  the  Rocky 
Mountains,  the  air  tends  always  to  be  com- 
paratively dry.  The  currents  coming  in  from 
the  Pacific  Ocean,  moist  at  the  outset,  lose 
much  of  their  moisture  under  contact  with  the 
81 


OUR   OWN    WEATHER 

mountains.  Currents  from  the  Gulf  of  Mexico 
and  the  Atlantic  Ocean,  the  only  other  con- 
siderable sources  of  moisture,  are  apt  not  to 
reach  that  far  northwestern  region,  and  when 
they  do  they  will  have  dried  out  more  or  less  on 
their  journey.  Currents  from  the  Great  Lakes 
have  at  most  no  extreme  amount  of  moisture. 
It  is  owing  to  the  condition  thus  established 
that  occasionally  a  cyclone  going  eastward  from 
Montana  by  the  northern  circuit  produces 
practically  no  rain. 

This  is  likeliest  to  occur  in  the  months  of 
October  and  November,  a  season  when  the 
northern  cyclone  is  rather  uniformly  well  de- 
fined and  vigorous.  Usually  it  does  produce 
rain,  but  it  is  apt  not  to  produce  much  until,  if  it 
is  going  by  the  northern  circuit,  it  has  come  into 
the  region  of  the  Great  Lakes,  or  until,  if  it  is 
going  by  the  southern  circuit,  it  has  gotten 
pretty  well  south.  The  truly  great  rains  are 
produced,  as  a  rule,  by  cyclones  from  the 
southwest,  especially  those  arising  in  western 
Texas  or  on  the  western  border  of  the  Gulf  of 
Mexico.  In  these  the  contest  is  likely  to  be 
from  the  very  start  between  currents  all  of  a 
high  degree  of  moisture. 

In  form  the  rain  area  is  of  the  greatest  irreg- 
82 


HOW  THE  STORM  BODIES  TRAVEL 

ularity.  Like  the  cloud  area,  while  more  or 
less  completely  surrounding  the  cyclone,  it  has 
commonly  a  wider  extension  forward  then  back- 
ward. The  extension  forward  has  been  thought 
to  show  a  proportion  to  the  rate  of  the  cyclone's 
progress.  Before  a  cyclone  moving  at  the  rate 
of  fifteen  miles  an  hour  the  rain  area,  it  has  been 
estimated,  will  reach  out  something  more  than 
four  hundred  miles,  and  something  more  than 
six  hundred  miles  before  one  moving  at  the  rate 
of  forty  miles  an  hour. 

Not  only  the  area,  but  also  the  fall,  of  rain  is 
greater  in  advance  of  the  cyclone  than  behind 
it.  Oftener  than  not  the  point  of  heaviest  rain- 
fall is  rather  directly  on  the  line  that  the  center 
of  the  cyclone  is  to  follow.  In  view  of  this  it 
has  been  argued  that  by  taking  up  the  heat, 
or  energy,  set  free  by  the  fall  of  rain  the  cyclone 
always  maintains  in  its  rainiest  quarter  a 
strength  greater  than  in  other  quarters,  and 
that,  under  the  force  of  this,  it  is  all  the  time 
forming  for  itself  a  perfectly  new  center  just 
along  the  line  of  the  greatest  rainfall.  But  the 
general  opinion  now  is  that,  while  the  cyclone 
does  get  some  addition  of  energy  from  the  fall 
of  rain,  it  owes  to  this  none  of  its  fundamental 
organization  and  movement. 
83 


OUR   OWN    WEATHER 

Between  its  own  inner  strength  and  the 
volume  of  rain  produced  there  appears  no  clear 
correspondence.  Often  a  cyclone  of  no  very 
low  air  pressure  at  the  center  is  accompanied  by 
heavy  rain.  The  rain  seems  to  be  really  but  a 
local  outburst  even  when  it  marks  the  cyclone's 
whole  course.  It  is  more  at  one  time  and  place 
and  less  at  another,  according  to  the  condition 
of  temperature  and  humidity  offered  just  then 
and  there  to  the  cyclone  at  its  approach. 

There  has  been  discerned,  however,  a  diurnal 
period  both  in  the  progress  of  a  cyclone  and  in 
the  rainfall.  The  cyclone's  advance  is  apt  to 
be  a  fourth  more  rapid  through  the  latter  part 
of  the  afternoon  and  during  the  evening  than 
at  other  times  of  day,  and  it  is  also  in  the  latter 
part  of  the  day  that  we  get  most  rain.  In  this 
the  rain  and  the  cyclone  probably  do  not  much 
influence  each  other,  but  are  both  influenced 
by  the  daily  decline  of  the  sun. 

It  is  due  especially  to  the  fitfulness  of  the  rain 
areas  that  the  official  weather  forecaster  wins 
from  his  public  so  seldom  any  but  words  of 
disdain.  No  man  serves  with  more  faithful- 
ness and  intelligence;  few  men  are  of  more 
direct  and  practical  use  in  the  world.  But 
because  he  cannot  tell  us  just  to  the  minute 
84 


HOW  THE  STORM   BODIES  TRAVEL 

when  to  wear  our  rain-coats  or  carry  our 
umbrellas  we  all  incline  to  regard  him  as  a  quite 
futile  and  ridiculous  person.  The  moment  even 
a  quite  dim  cyclone  appears  anywhere  in  the 
country  he  knows  of  it  and  reports  it.  He  tells 
precisely  where  it  is  to-day  and  with  fair  pre- 
cision (in  most  instances)  where  it  will  be  to- 
morrow. He  describes  it  in  all  its  qualities  and 
force.  He  predicts  with  some  certainty  what 
is  to  be  the  general  scope  and  direction  of  its 
rain  tract.  But  because  this  tract  is  bound 
to  narrow  and  widen,  bow  in  and  bulge  out,  in 
a  way  that  no  one  can  foresee  his  rain  predictions 
must  be  for  many  places,  especially  along  the 
borders  of  the  course,  no  more  than  probabil- 
ities. He  frankly  offers  them  for  no  more.  But 
at  any  place  where  they  happen  not  to  become 
fully  realized  the  discontent  is  as  great  as  if 
they  had  been  solemn  pledges. 

If  the  matter  were  better  understood  this 
would  not  be  so.  No  one  can  follow  the  work 
of  the  Weather  Bureau  with  any  care  and  not 
be  brought  to  wonder  that,  of  a  thing  so  largely 
hidden  from  the  eye  and  apparently  so  without 
order  as  the  weather,  so  much  can  really  be  told 
and  foretold.  The  Weather  Bureau,  indeed,  is 
an  institution  toward  which  we  ought  to  be  at 
85 


OUR   OWN    WEATHER 

pains  to  cultivate  a  better  loyalty.  It  has,  I 
fancy,  a  need  of  all  the  friends  it  can  win.  It  is 
not  political ;  it  has  no  part  in  the  elections  ex- 
cept, perhaps,  to  be  condemned  when  Election 
Day  turns  out  nasty.  Consequently,  when  it 
appeals  to  Congress,  the  one  source  of  its  liveli- 
hood, and  at  the  same  time  a  body  to  whom 
nothing  else  is  quite  so  vital  as  the  elections, 
it  gets,  no  doubt,  never  any  too  eager  a  com- 
pliance. 


VII 


THE  BODY  THAT  SCATTERS  THE  AIR  AROUND 
AND  MAKES  FAIR  WEATHER 

THE  weather  is  so  much  more  impressive  to 
us  in  its  stormy  than  in  its  fair  manifesta- 
tions that  we  naturally  give  the  atmospheric 
organization  which  specially  produces  these  the 
foremost  place.  This  organization,  as  we  have 
just  seen,  is  the  cyclone.  But  there  is  another 
atmospheric  establishment  that  in  the  making 
of  the  weather  is  of  quite  as  much  importance 
as  it.  This  is  one  in  which  the  air,  under  the 
force  of  some  overcharge  up  in  the  region  of  the 
permanent  eastward  drift  of  the  general  at- 
mosphere, spills  down  and  then  runs  out, 
flooding,  as  it  were,  a  great  area  of  the  country. 
Coming  for  the  most  part  from  very  high  up 
this  air  is  prevailingly  dry  and  cool  and  the 
spread  of  it  produces  fresh,  fair  weather. 

The  overreaching  of  the  currents  in  their 
haste  to  get  into  the  central  pour,  added  to  the 
97 


OUR   OWN    WEATHER 

deflecting  force  of  the  earth's  rotation,  sets  the 
whole  organization,  just  as  in  the  case  of  the 
cyclone,  into  more  or  less  of  a  whirl.  But  since 
the  central  pour  is  a  descent  instead  of  an  ascent, 
a  draft  down  the  chimney  instead  of  up  the 
chimney,  as  in  the  cyclone,  the  direction  of  the 
whirl  is  just  the  opposite  of  that  of  the  whirl 
in  the  cyclone.  It  is  what,  to  a  person  placed  at 
the  center,  would  be  from  left  to  right,  or  the 
same  as  the  direction  of  the  movement  of  the 
hands  of  a  clock.  Because  of  this  complete 
reversal  of  the  movement  of  the  cyclone  the 
organization  is  known  as  an  anticyclone. 

It  is  also  known  as  an  area  of  high  pressure, 
or,  briefly,  in  weather  reports  and  maps  as  a 
"high."  This  marks  another  and  a  more 
fundamental  contrast  which  it  offers  to  the 
cyclone.  Whereas  in  the  central  region  of  a 
cyclone  the  air  always  shows,  as  weighed  by  the 
barometer,  a  pressure,  or  weight,  below  the 
normal — that  is,  something  below  thirty  inches 
— in  the  central  region  of  an  anticyclone  it 
shows  always  a  pressure  of  something  more 
than  thirty  inches.  This  excess  may  be  very 
slight.  In  the  larger  number  of  instances  the 
highest  pressure  shown  is  only  30.2  inches. 
This  marks  a  rather  feeble  organization  and  is 
98 


FAIR    WEATHER 

especially  frequent  in  summer  anticyclones. 
But  even  in  strong  winter  anticyclones  a  pres- 
sure as  high  as  30.8  inches  is  rare,  a  record  made, 
perhaps,  two  or  three  times  in  a  year.  Never- 
theless, a  pressure  of  30.9  is  not  startling,  and 
pressures  yet  higher  do  sometimes  occur.  One 
of  31.42  inches  reported  from  a  Canadian  sta- 
tion just  beyond  the  northern  border  of  Mon- 
tana is  nearly,  if  not  quite,  the  highest  ever 
reported  from  any  part  of  the  region  of  observa- 
tion covered  by  our  own  and  the  Canadian 
weather  service. 

We  have  vaunted,  and  with  good  warrant, 
the  great  extent  possible  to  the  cyclone.  But 
in  this  the  cyclone  cuts  only  a  small  figure 
beside  the  anticyclone.  An  anticyclone  may 
not  only  extend  from  ocean  to  ocean  and  from 
Canada  to  the  Gulf,  but  also  so  far  overrun  the 
borders  of  the  country  that  on  the  weather 
map,  which  is  limited  pretty  nearly  to  the 
United  States,  it  appears  as  boundless.  Yet  it 
will  not  be  boundless.  It  will  not  be  just  an 
atmospheric  condition  spread  lawlessly  about 
and  shading  off  imperceptibly  into  nothing. 
Its  outer  definition,  to  be  sure,  will  nowhere 
show  with  such  distinctness  that  one  could 
travel  to  it  and  from  direct  observation  say 
99 


OUR    OWN    WEATHER 

"Here  the  thing  ends."  But  with  whatever 
dimness,  there  will  still  be  an  individual  area 
decisively  marked  off  within  which  all  the 
movements  of  the  lower  air  have  relation  and 
symmetry  to  a  whirling  core  where  the  air 
from  high  levels  is  in  steady  descent  and  out- 
flow, and  the  whole  organization  will  be  capable 
of  progression. 

Form  and  Movements  of  the  Anticyclone 

There  are,  however,  in  the  areas  of  high  pres- 
sure, as  in  those  of  low  pressure,  all  degrees 
of  development,  beginning  in  what  is  scarcely 
more  than  a  disposition  and  ending  in  a  com- 
plete organization;  and  they  often  achieve 
quite  a  career  and  prove  themselves  quite 
efficient  anticyclones  without  coming  to  full 
perfection.  At  their  best  they  never  show  the 
trim,  close,  intense  formation  of  which  the 
cyclone  is  capable.  Being  fairer  in  their  effects 
than  cyclones  are,  they  enjoy,  on  the  whole,  a 
better  welcome.  But  they  are  not  near  so 
piquant  or  picturesque,  unless,  indeed,  we 
should  think  of  them — and  this  we  well  may — 
as  having  the  amiability  and  informality  that 
go  with  the  best  kind  of  largeness. 
100 


FAIR    WEATHER 

As  charted  on  the  weather  map  the  cyclone 
often  shows  nearly  the  form  of  a  true  circle, 
with  the  air  pressure  increasing  from  the  center 
outward  on  all  sides  by  the  sharpest  and  yet 
perfectly  regular  gradations.  In  what  is,  per- 
haps, its  trimmest  form  the  anticyclone  has 
been  described  as  a  triangle  with  the  corners 
rounded  off.  It  shows  oftenest  as  a  long, 
rather  uncertain  oval.  The  air  flows  constantly 
out  from  the  center  on  all  sides,  and  the  pres- 
sure constantly  decreases  from  the  center  out- 
ward. But  the  decrease  of  the  pressure  is  by 
grades  wide  and  easy  and  of  uneven  extension, 
and  the  movement  of  the  air  is,  in  consequence, 
gentle.  Not  until  the  currents  have  reached 
the  borders  of  a  cyclone,  where  the  abnormally 
low  pressure  within  the  cyclone  offers  them,  as 
it  were,  a  swift  run  downhill,  do  they,  as  a  rule, 
attain  a  stormy  velocity.  They  very  often 
attain  it  then,  and  simply  their  eager  inrush  is 
what  makes  the  high  west  and  northwest  wind 
always  encountered  on  the  west,  or  rear,  side  of 
a  strong  cyclone. 

Whereas  the  cyclone  is  an  area  of  warm  air, 
the  anticyclone  is  an  area  of  cool  air.  But  as 
in  a  cyclone  the  air  is  not  of  like  warmth 
throughout,  so  in  an  anticyclone  it  is  not 


OUR   OWN    WEATHER 

throughout  of  like  coolness.  The  north  and 
west  quarters  of  an  anticyclone  are,  as  a  rule, 
warmer  than  the  east  and  south  quarters.  The 
air  is  extremely  cold  in  the  earlier  stages  of  its 
descent,  for  the  descent  commonly  begins  up  at 
a  height  of  about  five  miles.  The  depth  of  the 
anticyclone  is,  therefore,  nearly  double  that  of 
the  cyclone.  The  outflow  is  not  all  at  the  lower 
levels,  but  appears  even  high  up.  The  organi- 
zation as  a  whole  is,  as  it  were,  an  inconceivably 
deep  cell,  or  funnel,  built  up  out  of  air  and  with 
air  flowing  through  it,  but  permitting  more  or 
less  leakage  all  the  way  from  the  top  to  the 
bottom. 

Like  the  cyclone,  the  anticyclone  makes  its 
first  appearance  commonly  in  the  Far  West. 
Either  it  arises  somewhere  on  the  northern 
Pacific  coast  or  it  comes  in  from  Alberta,  the 
Canadian  province  lying  just  north  of  the  states 
of  Idaho  and  Montana.  The  latter  is  by  far  its 
more  frequent  course.  From  Alberta,  it  will 
be  remembered,  come  also  the  larger  number  of 
cyclones.  But  when  entering  from  Alberta  the 
anticyclone  does  not,  like  the  cyclone,  enter 
almost  exclusively  by  way  of  Montana ;  it  may 
come  in  through  North  Dakota  or  Minnesota  or 
over  the  Great  Lakes,  or  even  east  of  them. 
102 


FAIR   WEATHER 

Occasionally  it  becomes  a  strong  influence  in  the 
United  States  without  actually  crossing  the 
border. 

Having  touched  or  crossed  the  border,  the 
anticyclone  shows,  like  the  cyclone,  a  decided 
preference  for  a  direct  eastward  course.  Yet, 
like  the  cyclone,  it  often  drops  down  into  the 
southern  circuit,  and,  traveling  that  circuit, 
it  is  much  apter  than  the  cyclone  to  leave  the 
country  at  some  point  on  the  middle  or  south 
Atlantic  coast.  When  it  arises  on  the  Pacific 
coast  it  may  move  eastward  along  the  northern 
border  until  it  has  crossed  the  Rocky  Moun- 
tains, and  then  proceed  by  either  the  northern 
or  the  southern  circuit.  But  it  may  take  at 
once  a  strong  southeastward  course,  and,  cross- 
ing the  mountains  by  way  of  Colorado,  proceed 
rather  directly  to  the  south  Atlantic  coast. 

The  anticyclone,  then,  follows  in  general 
about  the  same  courses  as  the  cyclone.  But 
it  does  not  follow  them  with  as  much  energy. 
It  betrays  more  often  than  the  cyclone  a  dis- 
position to  loiter,  and  when  it  travels  it  travels 
with  less  swiftness.  Its  average  rate  of  progress 
has  been  calculated  to  be  in  winter  twenty-seven 
miles  an  hour  to  the  cyclone's  thirty-two,  and 
in  summer  twenty-one  miles  an  hour  to  the 
103 


OUR    OWN    WEATHER 

cyclone's  twenty-six.  Its  ordinary  passage  over 
a  given  place  is  about  a  day  longer  than  the 
cyclone's.  When  one  is  traveling  directly  upon 
the  heels  of  the  other,  as  is  oftener  than  not  the 
case,  a  period  of  six  or  seven  days  will  cover  for 
both  the  whole  coming  and  going  and  see  the 
way  clear  for  a  succeeding  couple  And  inas- 
much as  the  almost  constant  succession  of  such 
couples  is  what,  more  than  anything  else,  de- 
termines the  weather  from  day  to  day  over  all 
the  country  east  of  the  Rocky  Mountains,  it 
long  ago  became  common  observation  that  our 
weather  comes  to  us  in  periods  of  three  days. 

How  Cyclones  and  Anticyclones  Work  Together 

While  in  the  ordinary  way  a  cyclone  is 
directly  followed  by  an  anticyclone,  yet  it  is 
not  so  always.  Before  the  anticyclone  has 
definitely  diffused  over  the  country  its  clearing 
and  freshening  effect  there  has  arisen  some- 
where and  come  into  sway  another  cyclone. 
This  puts  the  weather  out  of  half  its  order  and 
gives  to  every-day  human  experience  an  added 
proof  that  most  of  the  annoyance  of  life  is  due 
to  the  fact  that  things  will  not  adhere  to  their 
habit.  There  is  for  the  time  not  an  entire 
104 


FAIR    WEATHER 

obliteration  of  the  three -day  period,  but  a 
kind  of  blurring  and  bunching  up,  with  a  pas- 
sage of  bad  weather  succeeded,  not  by  good 
weather,  but  by  another  passage  of  bad,  and 
with  so  little  break  between  that  the  two  show 
as  one  and  so  become  to  human  patience  quite 
outrageous. 

This  is  an  irregular  proceeding,  but  of  course 
it  is  in  itself  quite  as  natural  and  lawful  as  the 
other.  The  cyclone,  according  to  the  opinion 
now  most  held,  is  not  so  much  the  partner  of 
the  anticyclone  as  its  creation  and  servant. 
It  is  formed  always  on  the  edges  and  under  the 
force  of  the  anticyclone.  Even  if  it  arises,  as 
it  often  does,  when  an  area  of  high  pressure  is 
definitely  marked  nowhere  in  the  country,  it  is 
believed  to  be  due  to  the  influence  of  such  an 
area,  an  influence  felt  before  the  body  exerting 
it  becomes  visible. 

The  fundamental  exchange  and  distribution 
of  air  between  the  hot  equatorial  and  the  cold 
polar  regions  is  thought  to  be  going  on  with 
more  abundance  and  vigor  just  over  the  north- 
ern part  of  the  North  American  continent  than 
perhaps  anywhere  else  in  the  northern  hemi- 
sphere. It  happens  just  here  with  especial 
frequency,  therefore,  that  under  the  disparities 
105 


OUR   OWN    WEATHER 

and  stress  of  this  exchange  and  distribution 
air  is  driven  down  to  the  earth  in  the  form  of 
anticyclones.  To  relieve  the  stress  and  dis- 
parities which  they  themselves  produce  below 
the  anticyclones  set  up  the  cyclone,  and  by  it  so 
much  of  the  air  as  proves  to  be  out  of  place  and 
not  desired  below  is  carried  aloft.  If  one 
cyclone  is  not  enough  to  do  the  work  they  set 
up  two,  or  whatever  number  may  be  required. 
Consequently,  the  cyclones  very  often  out- 
number the  anticyclones.  If  the  number  of 
cyclones  crossing  the  country  in  the  course  of 
a  year  is,  say,  a  hundred  and  ten,  the  number  of 
anticyclones  crossing  is  likely  to  be  about 
ninety.  They  are  distributed  through  the  year 
in  much  the  same  proportion  as  the  cyclones, 
varying  from  an  average  of  four  in  June  to  an 
average  of  from  ten  to  twelve  in  January  and 
being  considerably  more  frequent  and  more 
potent  through  the  whole  winter  half  of  the 
year  than  through  the  summer  half. 

An  anticyclone  of  real  influence  never  fails 
to  diffuse  over  the  country  clear  weather  and 
gentle  winds.  Under  its  advance  the  tem- 
perature falls,  dropping  in  extreme  cases  as 
much  as  thirty  degrees  below  the  normal. 
Under  its  departure  the  temperature  gradually 
106 


FAIR   WEATHER 

rises.  Under  its  presence  the  general  body  of 
the  air,  being  then  dry  and  without  much  mo- 
tion, gives  the  sunshine  free  access  to  the  earth, 
which  thus  acquires  more  heat  than  it  other- 
wise would  and  imparts  more  to  the  air  that 
lies  in  contact  with  it.  The  middle  of  the  day 
is,  therefore,  relatively  warm.  At  night  the 
dry,  still  air  permits  rapid  loss  of  heat  from  the 
earth  and  from  the  air  nearest  it,  and  the  night 
is  relatively  cool. 

The  rapid  warming  of  the  lower  air  favors  dur- 
ing the  day  a  steady  ascent  and  descent  of  warm 
and  cool  bodies  of  air  with,  at  the  height  of 
about  a  mile,  condensation  of  moisture  from 
the  ascending  warm  bodies  into  loose  masses  of 
white  or  gray  clouds — cumulus  clouds — that 
float  a  little  way  and  then  are  dissipated,  and 
that  detract,  by  their  coming  and  going,  nothing 
from  the  general  clearness. 

The  rapid  cooling  of  the  lower  air  lessens  at 
night  its  power  of  rising,  but  puts  it  even  more 
out  of  balance  with  its  charge  of  moisture  than 
if  it  had  cooled  during  the  day  simply  by  rising. 
Often  the  moisture  is  deposited  on  the  earth 
in  the  form  of  dew  or  of  frost:  frosts,  in  their 
season,  are  peculiarly  an  anticyclone  product. 
As  often,  though,  it  is  not  deposited,  but,  still 
8  107 


OUR   OWN    WEATHER 

retained  in  the  lower  air,  condenses  into  fog. 
Summer  and  winter  lowland  fogs  are  a  frequent 
feature  of  the  otherwise  fair  anticyclone  weather. 
In  summer,  owing  to  the  intensity  of  the  sun- 
shine, they  disappear  wholly  and  quickly  with 
the  advance  of  day.  But  in  winter,  with  the 
sunshine  so  much  less  strong  and  its  period 
so  much  shorter,  they  often  last  the  whole  day 
through,  and  may,  if  the  anticyclone  proves  a 
lingering  one,  last  unbrokenly  for  a  number  of 
days. 

The  anticyclone's  propensity  to  linger,  added 
to  its  extreme  clearness,  works  out  into  not 
only  obstinate  fogs,  but  also  other  effects  that 
make  its  highest  virtue  seem  for  the  moment 
only  a  fault.  It  becomes  occasionally  what  is 
known  as  a  "dead  high,"  when  it  simply  stands 
still  and  lets  itself  pile  up.  The  effect  for  the 
time  and  in  the  region  involved  is  much  as  if 
we  had  been  robbed  of  a  good  part  of  our  at- 
mosphere. The  sunshine  pours  down  full 
strength  in  the  middle  of  the  day  and  makes 
everything  overhot ;  and  the  heat  pours  out  at 
night  and  leaves  everything  overcold.  Much 
more  often,  though,  what  the  anticyclone  does 
by  lingering  is  simply  to  prolong  for  about  a 
week  a  period  of  truly  fine  weather,  weather  of 
108 


FAIR    WEATHER 

no  more  than  seasonable  warmth  or  coldness 
and  with  the  air  always  fresh  and  dry. 

A  Country-wide  Weather  Procession 

It  is  mainly  between  the  Rocky  Mountains 
and  the  Atlantic  Ocean  that  the  cyclones  and  the 
anticyclones  exhibit  their  interplay  on  the 
large  scale  and  with  the  constancy  and  con- 
spicuousness  that  especially  make  the  weather 
of  the  United  States  unique  and  notable.  But 
they  have  also  a  large  influence  on  the  weather 
over  all  the  country  from  the  eastern  side  of  the 
Rocky  Mountains  west  ward  to  the  Pacific  Ocean. 
It  is  a  country  that,  with  respect  to  weather, 
might  be  described  as  a  group  of  petty  king- 
doms. Each  abides  in  nearly  complete  inde- 
pendence of  the  others  and  refuses,  more  or  less, 
to  have  any  weather  that  is  not  of  its  own  kind. 
The  three  great  north  and  south  mountain 
ranges — the  Rockies,  the  Sierra  Nevada  and 
Cascade  mountains,  and  the  Coast  Range — with 
the  numerous  cross  -  ranges,  build  up  barriers 
that  often  shut  foreign  weather  stoutly  out  and 
hold  domestic  weather  tightly  in.  The  result 
is  that  admirable  specimens  of  about  all  of  the 
well-marked  types  of  weather  that  the  earth 
109 


OUR   OWN    WEATHER 

anywhere  affords  are  to  be  found  in  this  one 
region.  Yet  over  it  all,  and  in  practically 
every  recess  of  it,  the  same  cyclonic  alternations 
and  progressions  that  come  into  the  clearest 
dominance  eastward  are  steadily  at  work. 

Many  of  the  cyclones  and  anticyclones  come, 
as  we  have  seen,  directly  from  the  Pacific  coast. 
Of  these  the  larger  number  cross  to  the  eastern 
side  of  the  Rocky  Mountains  up  near  the 
Canadian  border,  but  some  cross  in  the  middle 
latitudes  and  (of  the  cyclones,  not  of  the  anti- 
cyclones) some  in  the  south.  In  many  cases 
where  they  do  not  just  show  as  coming  from  the 
Pacific  coast  it  is  pretty  certain  that  they  do 
come  from  there.  And  when,  as  is  most  fre- 
quently the  case,  they  come  in  unmistakably 
from  Canada,  along  the  eastern  side  of  the 
Rocky  Mountains,  they  are  often  able  to  climb 
the  mountains  and  spread  out  as  freely  and 
potently  westward  and  southwestward  as  east- 
ward and  southeastward. 

The  cyclonic  procession  is,  therefore,  an 
affair  of  the  entire  country.  There  are  no  sec- 
tions that  need  sulk  and  say  that  it  may  be  a 
very  curious  and  fine  thing,  but  that  it  does  not 
concern  them.  It  concerns  us  all;  and  if  it 
were  as  open  to  our  sight  as  it  is  effective  in  our 


FAIR   WEATHER 

lives  we  should  never  have  to  be  urged  to  look 
at  it.  We  should  often  become  in  our  behavior 
like  a  body  of  school-children  whom  it  was 
sought  to  keep  in  their  seats  and  at  their  tasks 
just  at  the  moment  when  the  most  spectacular 
part  of  a  grand  military  parade  was  going  by. 
We  would  get  somehow  our  peep  out-of-doors 
under  the  very  nose  of  duty  and  authority. 
As  the  matter  stands,  however,  the  largest  per- 
mission ever  granted  and  the  best  point  of  view 
obtainable  enables  us  to  see  only  a  little.  That 
little,  though,  can  prove  immensely  interesting. 
Perfectly  bad  weather  may  become  positively 
pleasing  when  we  have  the  habit  of  definitely 
looking  at  it  and  realizing  to  ourselves  its  place 
and  proceeding  in  the  whole  movement  by  which 
all  the  weather  comes. 

Some  amends  are  made  us  for  the  scantness 
of  our  faculty  for  seeing  the  weather  by  the 
benevolence  of  the  Weather  Bureau.  The 
daily  weather  report,  read  in  the  light  of  just  a 
little  knowledge  of  the  subject,  becomes  quite  a 
different  affair  from  that  for  which  commonly 
we  have  nothing  but  disparagement;  and  the 
daily  weather  map,  for  any  one  who  has  learned, 
as  any  one  easily  can  learn,  how  to  avail  himself 
of  it,  makes  a  solid  contribution  to  the  steady 


OUR    OWN    WEATHER 

enjoyment  of  life.  As  portrayed  in  the  daily 
map  the  weather  gets  the  aspect  and  zest  of  a 
magnificent  game,  a  game  in  which  the  highs 
and  the  lows  are  shrewdly  and  potently  winning 
their  way  from  ocean  to  ocean  and  are  exhibit- 
ing, in  a  succession  of  grand  plays,  their  own 
particular  temperament  and  competency.  The 
weather  map  has  in  it,  therefore,  something  of  a 
thrilling  quality,  and  the  dullness  of  a  document 
is  not  in  the  least  its  character. 


VIII 

THE    WEST    INDIAN    HURRICANE    AND    ITS    PART 
IN    OUR   WEATHER 

IN  the  work  of  controlling  the  daily  varia- 
tions of  the  weather  the  continental  cy- 
clones and  anticyclones  are  called  upon  now  and 
then,  and  in  a  very  decisive  manner,  to  share 
with  another  atmospheric  organization,  the 
West  Indian  hurricane. 

Strict  hurricanes  never  arise  within  the 
borders  of  the  United  States  proper.  They 
are  exclusively  of  tropical  origin,  and  they 
became  an  American  product  only  by  the  an- 
nexation of  Porto  Rico  and  the  Philippines, 
regions  that  are  fairly  fruitful  in  them.  They 
find  a  natural  breeding-ground  in  the  latitudes 
where  the  comparatively  cool  trade-winds  brush 
along  or  thrust  into  the  equatorial  belt  of  slug- 
gish, overheated,  overmoist  air,  known  as  the 
doldrums.  They  arise  always  over  the  ocean  or 
over  islands  that  are  under  strong  oceanic  con- 
up 


OUR   OWN    WEATHER 

trol,  never  over  the  continents.  They  occur 
not  only  over  the  Atlantic  Ocean,  but  also  over 
the  Indian  Ocean  and  over  the  Pacific,  off  the 
southeast  coast  of  China.  In  the  East  they  are 
known  as  typhoons,  and  they  occur  both  north 
and  south  of  the  equator.  But  over  the 
Atlantic  they  occur  only  north  of  the  equator, 
and  they  either  arise  or,  at  any  rate,  first  come 
under  official  observation  almost  exclusively  in 
the  West  Indies. 

Of  West  Indian  hurricanes  important  enough 
to  be  officially  counted  there  were  121  in  the 
thirty  years  1880-1909.  They  came  8  in  June,  5 
in  July,  28  in  August,  40  in  September  and  40  in 
October.  Hurricanes  in  any  other  than  these 
five  months  are  not  unheard  of  in  the  West 
Indies,  but  they  are  extremely  rare;  and  of  the 
fact  of  their  occurring  with  such  uniformity 
there  only  in  the  latter  half  of  summer  and  the 
early  half  of  autumn,  and  of  the  further  fact  of 
their  entire  absence  from  the  South  Atlantic,  a 
very  interesting  explanation  has  been  offered. 

What  Confines  the  Hurricane  to  a  Given  Season 
and  Course 

Hurricanes  are  cyclones,  and  of  a  much  more 
sharply  defined,  much  tougher,  and  much  more 
120 


THE  WEST    INDIAN   HURRICANE 

forcible  organization  than  continental  cyclones. 
Their  whirl,  or  gyration,  like  that  of  continental 
cyclones,  is  unfailingly  from  right  to  left,  or 
contrary  to  the  movement  of  the  hands  of  a 
clock,  in  the  northern  hemisphere,  and  in  the 
southern  hemisphere  as  unfailingly  from  left 
to  right,  or  with  the  movement  of  the  hands  of  a 
clock.  This  proves  them  to  be,  at  their  organi- 
zation, subject  to  strong  deflection  under  the 
force  of  the  earth's  rotation. 

Just  at  the  equator  this  force  is  overmastering 
rather  than  deflective;  it  is  there  so  strong  that, 
so  to  say,  it  carries  things  all  its  own  way. 
Hurricanes,  in  order  to  become  cyclones,  must, 
therefore,  arise  not  too  near  the  equator.  The 
doldrums,  on  the  edges  of  which  they  always  do 
arise,  have,  it  will  be  remembered,  an  annual 
progress  north  and  south  in  their  adhesion  to 
the  sun.  They  are  at  their  farthest  north  in 
August  and  September;  and  since  this  is  also 
the  height  of  the  season  for  the  West  Indian 
hurricanes,  it  is  argued  that  only  when  the 
northern  border  of  the  Atlantic  doldrums  is 
most  removed  from  the  equator  are  atmos- 
pheric disturbances  arising  in  that  border  apt 
to  get  just  the  right  deflection  to  become 
cyclones. 

121 


OUR   OWN   WEATHER 

The  Atlantic  doldrums  lie  throughout  the 
year,  however,  more  north  of  the  equator  than 
south  of  it.  The  long  projection  of  Africa 
westward,  just  north  of  the  equator,  and  of 
South  America  eastward,  just  south  of  it,  so 
shapes  the  ocean  currents  that  the  water  in  the 
northern  part  of  the  South  Atlantic  is  always 
relatively  cool,  and  this  coolness  of  the  ocean 
surface  keeps  the  doldrums  always  relatively 
far  north.  Their  southern  border  at  the  south- 
ernmost migration  lies  in  part  directly  on  the 
equator  and  in  no  part  more  than  a  little  south. 
It  abounds  in  storms.  But  it  is  never  far 
enough  away  from  the  equator,  either  north  or 
south — just  as,  except  about  August  and 
September,  the  northern  border  almost  never 
is — for  the  storms  to  be  deflected  into  cyclones. 
And  this  is  the  explanation  offered  of  why  there 
are  no  hurricanes  over  the  South  Atlantic  and 
why  those  over  the  North  Atlantic  are  mainly 
the  occurrences  of  July,  August,  September,  and 
October.  It  illustrates  finely  how  land  and  sea 
and  atmosphere,  shone  upon  by  the  sun,  work 
all  together,  and  never  apart,  and  not  only  for 
the  moment,  but  through  the  months  and  the 
years,  to  produce  the  weather. 

There  is  another  condition,   as  curious  as 

122 


THE  WEST    INDIAN   HURRICANE 

those  just  explained,  that  affects  the  West 
Indian  hurricanes  perhaps  in  their  season,  and 
certainly  in  their  place,  of  arising  and  in  the 
courses  over  which  they  travel.  Mention  has 
already  been  made  (page  20)  of  the  fact  that 
in  the  regions  of  tropical  calm,  about  the 
thirtieth  parallel  of  latitude,  north  and  south, 
the  general  circulation  of  the  atmosphere  casts 
the  air  into  semi-permanent  belts  of  superior 
weight,  or  pressure,  and  that  the  northern  belt 
of  high  pressure  has  an  important  part  in  our 
own  weather.  One  way  in  which  we  experi- 
ence its  influence  is  in  the  control  it  exercises 
over  the  West  Indian  hurricanes.  It  is  always 
much  more  strongly  marked  over  the  sea  than 
over  the  land,  and  at  times  it  practically  dis- 
appears from  the  American  continent.  But  it 
abides  over  the  ocean,  a  well-defined  body  of 
air  with  an  anticyclonic  rotation,  lying  between 
our  own  southeastern  coast  and  the  northwest 
coast  of  Africa.  Because  of  its  clear  definition 
and  its  constancy  it  has  come  to  be  known  as 
the  permanent  North  Atlantic  anticyclone,  or 
"  high."  Except  that  it  is  more  extended,  more 
enduring,  and  of  greater  potency,  it  does  not 
differ  materially  from  the  oft-recurring  con- 
tinental anticyclones;  and  as  they  are  thought 
9  I23 


OUR    OWN   WEATHER 

to  be  provokers  of  the  continental  cyclone,  so 
is  it  thought  to  be  much  involved  in  the  setting 
up  of  the  West  Indian  hurricane.  The  hurri- 
canes arise  on  or  near  its  southern  and  south- 
western border;  and  in  the  course  of  the  hur- 
ricane season  their  ordinary  place  of  arising 
shifts  first  eastward  and  then  westward  in 
apparently  some  correspondence  with  shifts 
of  position  shown  by  the  anticyclone  itself. 

The  Hurricane's  Path  and  Speed 

But  the  most  open,  most  conspicuous  effect 
of  the  North  Atlantic  anticyclone  over  the 
West  Indian  hurricanes  is  the  compulsion  it 
holds  them  under  in  their  travels.  The  general 
circulation  of  the  atmosphere  in  the  region  of 
their  origin  carries  them  at  first  northwestward. 
They  cross  the  northern  border  of  the  tropics, 
and  then  the  permanent  eastward  drift  of  the 
atmosphere  in  the  north  temperate  zone  lays 
hold  of  them  and  carries  them  northeastward. 
Very  rarely  do  they  fail  to  make  in  a  general 
way  this  course.  But  with  what  directness 
they  may  make  it,  and  also,  in  some  measure, 
at  what  speed,  seems  to  be  determined  for  them 
largely  by  the  North  Atlantic  anticyclone. 
124 


THE  WEST    INDIAN    HURRICANE 

According  as  the  anticyclone  is  more  or  less 
extended  southward  and  westward  are  they 
driven  westward  before  recurving  and  held 
afterward  to  more  of  a  northward  than  north- 
eastward progress. 

Much  the  larger  number  manage  to  accom- 
plish their  entire  course  within  the  limits  of  the 
Atlantic  proper.  Starting  at  some  point  east 
or  southeast  of  Porto  Rico,  they  travel  curvingly 
northwestward  up  to  the  latitude  of  Florida,  and 
then,  at  a  greater  or  a  less  distance  east  of  the 
Florida  coast,  turn  northward  or  northeastward. 
Many,  however,  are  driven  into  the  Gulf  of 
Mexico;  and  when  so  driven,  and  having  re- 
curved, they  are  likely  to  invade  the  United 
States.  Once  in  a  while,  though,  the  strong 
western  extension  of  the  Atlantic  anticyclone 
prevents  them  from  recurving  at  all,  and  they 
push  into  Mexico  or  southwestern  Texas  and 
are  there  dissipated.  They  are  likeliest  to  be 
driven  far  west  in  the  month  of  September,  and 
it  is  in  that  month  that  we  are  apt  to  become 
most  aware  of  them  in  the  United  States. 

West  Indian  hurricanes  vary  greatly  in  their 
rate  of  travel.  Some  go  with  much  more 
rapidity  than  do  others;  and  they  show  dif- 
ferent speeds  in  different  parts  of  their  course. 
125 


OUR    OWN    WEATHER 

Up  to  the  beginning  of  the  recurve  they  move, 
it  has  been  estimated,  at  an  average  rate  of 
eighteen  miles  an  hour.  At  the  recurve  they 
suffer  a  retardation.  This  is  greater  or  less 
according  as  the  angle  of  recurve  is  narrow  or 
wide.  Occasionally  it  amounts  to  a  temporary 
stoppage,  commonly  to  such  a  slowing  up  as 
makes  the  average  rate  of  speed  at  the  recurv- 
ing-point  six  miles  an  hour. 

Any  check  put  upon  West  Indian  hurricanes 
in  their  travel  increases  the  intensity  of  their 
whole  organization.  They  become  more  vio- 
lent in  their  winds  and  their  rain  while  the 
detention  lasts;  and  after  it  is  removed  they 
steadily  increase  their  speed.  Their  average 
rate,  after  recurving,  is  thirty-five  miles  an  hour, 
or  three  miles  an  hour  more  than  the  average 
winter  progress  of  our  continental  cyclones. 
They  finish  their  course  and  disappear,  as  a  rule, 
in  the  western  Atlantic,  somewhere  between 
Florida  and  Newfoundland.  But  they  occa- 
sionally reach  Europe,  preferably  the  region 
between  Iceland  and  Norway. 

The   West    Indian    hurricane   has    a    great 

place  in  romance  and  in  history.     It  develops, 

oftener  than  not,  an  extreme  violence,  and  since 

its  course  lies  up  and  across  one  of  the  most- 

126 


THE  WEST    INDIAN    HURRICANE 

traveled  parts  of  all  the  ocean,  it  holds  a  great 
place  in  the  records  of  sea  disaster.  Columbus 
had  frightful  encounters  with  it  in  more  than 
one  of  his  western  voyages,  and  it  greatly 
heightens  the  thrill  and  picturesqueness  of  the 
story  of  the  discovery  of  America.  In  the 
stories  of  a  host  of  subsequent  navigators  it 
figures  as  salient ly.  In  spite  of  the  absence  of 
anything  like  systematic  weather  observation 
until  quite  recent  times,  it  has  been  possible  to 
compile  a  fairly  detailed  list  of  three  hundred 
and  fifty-five  hurricanes  arising  in  the  West 
Indies  between  1493  and  1855.  In  this  list  the 
later  centuries  naturally  supply  more  items 
than  do  the  earlier;  yet  fifty-four  are  of  the 
period  prior  to  1700,  and  twenty-two  are  of  that 
prior  to  1600.  So  much  of  a  record  from  times 
little  given  to  leaving  records  shows  something 
of  the  great  impression  that  the  West  Indian  hur- 
ricane has  been  making  on  seafaring  men  from 
the  very  beginning  of  their  acquaintance  with  it. 
It  has  made  scarcely  less  impression  on  the 
sea  romancers.  They  have  found  in  it  as  sure 
a  dependence  for  fluttering  the  hearts  of  fond 
readers  as  in  the  freebooters  and  buccaneers. 
The  latter,  so  long  since  dead  and  forever 
vanished,  must  have  been  for  some  time  back 
127 


OUR   OWN    WEATHER 

a  cooling  material.  And  the  hurricane  as  well, 
though  it  still  survives  in  all  of  its  old-time 
form  and  vigor,  must  be  radiating  some  of  its 
romance.  It  quite  holds  its  own  relatively 
among  the  great  dangers  of  the  sea.  But  under 
the  substitution  of  steel  steamships  for  wooden 
sailing-vessels  and  the  installation  of  wireless 
telegraph  and  international  weather  observation 
it  is  becoming,  like  most  of  the  others,  daily 
more  and  more  avoidable. 

Constitution  and  Behavior  of  the  Hurricane 

It  was  through  study  of  West  Indian  hurri- 
canes that  meteorologists  first  came  to  anything 
like  a  clear  perception  of  the  mechanism  of 
atmospheric  organizations.  They  exhibit  this 
mechanism  in  its  very  highest  perfection.  Be- 
side them  the  continental  cyclone  is  a  compara- 
tively formless  affair.  They  have  never  such 
wide  extent  as  it  reaches  at  its  greatest.  Their 
diameter  may  be  as  much  as  five  hundred  or 
six  hundred  miles,  but  is  on  an  average  only 
about  three  hundred.  In  height  hurricanes  are 
often  as  much  as  six  miles,  while  the  continental 
cyclone  scarcely  exceeds  three  miles.  They  are 
in  form  more  nearly  circular  than  it,  and  are  in 
128 


THE  WEST    INDIAN    HURRICANE 

all  respects  more  evenly  and  compactly  con- 
stituted. 

A  well  -  rounded,  ever-renewing,  swiftly  rota- 
ting structure  of  wind  and  rain  creates  and 
maintains  within  itself,  by  its  strong  upward 
suction,  a  region  of  comparative  calm.  Be- 
cause of  the  strength  of  the  storm  circle  the 
quieter  condition  established  at  the  center  is 
much  more  marked  in  hurricanes  than  in  the 
continental  cyclone.  But  it  is  not,  even  in 
hurricanes,  strictly  a  calm.  The  rains  cease, 
the  winds  fall,  the  clouds  disperse,  and  the  sky 
becomes  perfectly  clear.  But  the  waters  re- 
main troubled,  and,  under  the  cross-running  of 
waves  projected  inward  from  all  sides,  may  be 
even  rougher  than  they  are  in  the  circle  of 
storm.  And  the  winds,  although  they  fall, 
keep  a  velocity  of  from  six  to  ten  miles  an  hour, 
and  are  liable  to  break  into  gusts  of  a  velocity 
of  from  eighty  to  ninety  miles.  To  ships  over- 
taken by  a  hurricane  and  surviving  long  enough 
to  be  embraced  by  the  central  calm  it  shows  by 
contrast  a  sufficient  light  and  graciousness  to 
justify,  no  doubt,  the  name  bestowed  on  it  long 
ago,  that  of  "the  eye  of  the  storm."  But  they 
gain  in  it,  certainly,  no  true  repose.  Nor  are 
they  permitted  to  enjoy  it  long,  for  at  its 
129 


OUR   OWN    WEATHER 

largest  it  is  not  likely  to  be  more  than  twenty  or 
thirty  miles  across.  Moreover,  the  danger  of 
the  passage  out  of  it  is  apt  to  be  greater  than 
that  of  the  passage  in,  for  at  the  front  of  the 
hurricane  the  wind  and  rain  increase  gradually 
and  then  diminish  gradually  toward  the  central 
region,  while  at  the  rear  they  start  up  from  that 
region  with  perilous  abruptness. 

Hurricanes,  like  continental  cyclones,  give 
forewarning  of  themselves  by  sending  out  aloft 
streamers  of  cirrus  clouds.  They  do  it,  indeed, 
with  a  constancy  and  definiteness  which  the 
continental  cyclones  are  not  capable  of.  The 
streamers  run  out  with  about  equal  clearness 
from  all  quarters,  but  are  more  extended  in  the 
direction  of  the  hurricane's  progress.  They 
have  a  difference  of  character,  easily  distin- 
guished by  practised  observers,  according  to  the 
size  and  intensity  of  the  hurricane.  They  also 
mark  this  in  the  degree  of  their  extension. 
They  extend  to  a  distance  from  the  center  of 
from  three  hundred  to  four  hundred  miles  in 
hurricanes  of  small  diameter  and  great  violence, 
and  in  those  of  large  diameter  and  less  violence 
to  a  distance  of  from  seven  hundred  to  eight 
hundred  miles. 

A  fair  forewarning  of  hurricanes  is  given  also 
130 


THE  WEST    INDIAN    HURRICANE 

in  the  disturbance  they  raise  in  the  waters  of  the 
sea.  This  disturbance  is  so  widely  propagated 
that  it  may  announce  them  while  they  are  yet 
two  or  three  days'  travel  away.  The  form  of 
it  at  its  margin  is  a  peculiar  long  swell,  arising 
and  continuing  from  no  apparent  cause. 

In  a  hurricane,  even  more  decisively  than  in  a 
continental  cyclone,  the  winds  blow  in  toward 
the  center  from  all  quarters.  They  begin  as  a 
gentle  breeze,  but  increase  steadily  in  to  the 
margin  of  the  central  calm,  where  on  the  front 
they  have  a  gradual  and  on  the  rear  an  abrupt 
fall.  When  the  winds  have  mounted  to  a  mean 
velocity  of  from  thirty-five  to  forty  miles  an  hour 
rain  begins.  It  comes  at  first  in  brief  showers, 
during  which  the  wind  is  split  up  into  gusts  of  a 
velocity  of  from  fifty -five  to  sixty  miles  an  hour. 
Farther  on  the  rain  becomes  continuous,  but 
has  rises  and  falls  in  its  intensity.  In  corre- 
spondence with  these  the  wind  breaks  up  into 
great  blasts  and  may  show  a  force  of  one  hun- 
dred, one  hundred  and  ten,  or  even  one  hundred 
and  twenty  miles  an  hour.  The  rainfall  is  both 
more  continuous  and  more  copious  in  large 
storms  than  in  small.  In  the  smaller  storms 
the  rain  area  has  an  average  extension  of  one 
hundred  and  fifty  miles  forward,  but  of  only  one 


OUR    OWN    WEATHER 

hundred  miles  backward.  In  the  larger  storms 
it  is  distributed  more  equally  over  the  several 
quarters,  and  its  average  outward  extension  is 
about  five  hundred  miles. 

The  Hurricane  as  It  Operates  in  the  United  States 

The  most  destructive  storms  experienced  in 
the  United  States  are  West  Indian  hurricanes. 
About  every  year  we  are  apt  to  have  one 
come  near  enough  to  us  to  make  a  substantial 
impression  at  points  on  the  Atlantic  or  Gulf 
coast,  and  somewhat  inland.  Every  year  along 
the  coast,  but  more  especially  some  what  out  from 
it,  they  are  a  menace  to  shipping  throughout  the 
hurricane  season.  Against  the  danger  which 
they  threaten  there  is  now  a  large  protection  in 
the  efficiency  of  the  government  weather-obser- 
vation service.  When  ships  are  overtaken  by 
a  West  Indian  storm  it  is  apt  in  these  days  to 
be  through  their  own  disregard  of  true  and 
timely  warnings.  Such  disregard  is  so  frequent 
as  to  offer  a  standing  example  of  human  heed- 
lessness.  It  often  happens,  though,  that  with 
all  possible  foresight  and  efficiency  positions  of 
safety  cannot  be  reached.  The  West  Indian 
hurricane  is  still,  therefore,  not  entirely  denied 
its  high  feasts  of  ships  and  seamen. 
132 


THE  WEST    INDIAN    HURRICANE 

On  meeting  with  land  hurricanes  are  apt  to 
suffer  a  rebuff.  They  sometimes  dissipate  en- 
tirely at  the  first  encounter.  The  United 
States  often  get  the  benefit  of  this  character- 
istic. One  will  come  driving  in  toward  our 
shores  with  the  greatest  violence,  and  the 
Weather  Bureau  will  send  out  its  sharpest 
warnings,  and  then  we  hear  nothing  more  of  it 
but  that  it  has  died  out.  A  more  common 
thing  is  for  them  to  keep  enough  strength  to 
cross  the  shore,  but  not  enough  to  travel  far  or 
be  much  of  a  storm  afterward.  Most  frequently, 
having  landed,  they  tame  down  into  ordinary 
continental  cyclones,  make  a  long  northeasterly 
course,  and,  while  remaining  sturdy,  are  not 
really  violent.  They  have  no  well-marked 
choice  in  their  place  of  landing,  but  they 
come  in  somewhat  oftener  across  the  Gulf 
coast  than  across  the  south  Atlantic  coast, 
and  rarely,  if  ever,  across  the  north  Atlantic 
coast. 

Now  and  then  one  gets  fully  landed  with  its 
strength  scarcely,  if  at  all,  diminished.  There- 
upon, unfailingly,  a  new  chapter  is  added  to 
our  history  of  devastating  storms.  By  a  course 
often  quite  incalculable — perhaps  from  Texas 
straight  northward  and  eastward  to  the  Great 


OUR   OWN    WEATHER 

Lakes  and  the  St.  Lawrence  valley,  or  straight 
eastward  through  the  Gulf  states  and  then 
northeastward  through  the  Atlantic  states; 
perhaps  straight  northward  from  Florida  to 
the  St.  Lawrence  valley;  or  perhaps  straight 
northwestward  from  South  Carolina  to  Minne- 
sota— the  hurricane  drives  fiercely  across  the 
country,  wrecking  structures,  flooding  farms 
and  towns,  and  not  infrequently  destroying 
life. 

Such  visitations  occur,  not  as  often  as  once 
a  year,  but  somewhat  oftener  than  once  in  two 
years.  They  have  come  one  a  year  for  two 
years,  for  three  years,  and  even  for  five,  with  a 
year  intervening  when  there  was  none.  A  few 
times  they  have  come  two  in  a  single  year. 
There  has  been  in  their  distribution  no  equality. 
September  is  the  month  of  their  greatest  fre- 
quency and  also  of  their  greatest  severity; 
after  that,  August;  then  October.  Except  in 
these  three  months  severe  hurricanes  are  not 
expected,  nor  more  than  the  fewest  of  any  sort. 
Yet  of  those  notable  enough  in  a  period  of 
twenty  years  to  be  given  particular  record  one 
occurred  in  November,  a  month  never  rated 
as  in  the  hurricane  season. 


THE  WEST    INDIAN    HURRICANE 

Storms  that  Broke  All  Records 

In  September,  1875,  a  hurricane  came  up 
from  somewhere  in  the  region  of  Barbados, 
entered  the  Gulf  of  Mexico  near  Florida,  crossed 
to  Texas,  and,  settling  with  all  its  force  on  the 
town  of  Indianola,  demolished  all  but  the  merest 
fraction  of  it  and  destroyed  one  hundred  and 
seventy-six  lives.  Having  finished  with  In- 
dianola, it  turned  northeastward,  its  ferocity 
now  considerably  abated,  crossed  over  to  Vir- 
ginia, and  from  there  went  out  again  to  sea. 
This  was  classed  at  the  time  by  the  govern- 
ment Weather  Bureau  as  the  severest  storm 
that  had  ever  occurred  in  the  United  States 
"since  the  establishment  of  the  weather  ser- 
vice." But  it  was  much  exceeded  in  violence 
by  one  still  in  fresh  memory,  the  Galveston 
storm  of  September,  1900. 

This  has  been  authoritatively  pronounced 
"the  severest  and  most  destructive  hurricane  in 
the  storm  annals  of  the  Western  Hemisphere." 
It  arose,  like  the  other,  in  the  region  of  Bar- 
bados. Traveling  first  westward  and  then 
northward,  it  nipped  into  the  southwestern 
coast  of  Florida  and  wrecked  a  number  of 
vessels.  Then  by  a  course  a  little  north  of 


OUR    OWN    WEATHER 

true  west  it  crossed  the  Gulf  of  Mexico,  and  in 
crossing  was  encountered  by  the  steamship 
Louisiana,  which  passed  straight  through  the 
center  of  it,  fought  with  gales  blowing  at  more 
than  a  hundred  miles  an  hour,  and  still  sur- 
vived. All  the  way  the  storm  increased  in 
strength  steadily  but  rather  slowly.  It  did  not 
attain  its  greatest  force  until  it  neared  Galves- 
ton,  and  only  just  there  did  it  deal  a  truly 
great  destruction.  Six  thousand  people  lost 
their  lives  by  it,  and  property  was  destroyed 
to  the  value  of  twenty  million  dollars.  From 
Galveston  it  passed,  much  modified,  into  Kan- 
sas and  Nebraska,  and  then  eastward  across 
Iowa  and  Wisconsin.  Suddenly  recovering 
much  of  its  strength,  it  swept  over  the  Lakes 
and  down  the  St.  Lawrence  valley,  with  large 
damage  to  property  on  both  land  and  water. 
It  occupied  just  a  week  with  its  devastating 
carnival  along  and  within  our  borders. 

Such  an  extreme  performance  as  that  of  the 
Galveston  storm  is,  of  course,  not  to  be  classed 
as  one  of  the  regular  features  of  our  weather. 
We  may  believe,  as  well  as  hope,  that  it  will 
not  soon,  if  ever,  be  repeated.  But  it  illus- 
trates without  any  real  exaggeration  how  truly 
an  institution  of  our  weather  the  West  Indian 
136 


THE  WEST    INDIAN    HURRICANE 

hurricane  is.  On  occasions  in  the  later  summer 
and  the  earlier  autumn  the  oceanic,  or  West 
Indian,  cyclone  steps  in  and  simply  takes  the 
place  of  the  continental  cyclone.  Except  that 
it  tends  to  be  more  violent,  it  does  not  differ 
from  the  latter  in  either  its  behavior  or  effect. 
In  our  experience  of  them  we  cannot  tell  one 
from  the  other.  One  as  well  as  the  other  has 
always  as  a  control  the  anticyclone,  and  the 
three  together  make  the  frame  on  which  is 
shaped  the  general  daily  weather  of  the  country. 


IX 

WINTER   AND   SUMMER   WEATHER 

INTERVALS  of  a  day  or  of  a  few  days  each 
are  not  uncommon  when  over  some  part 
of  the  country  no  cyclone  or  anticyclone  is  in 
clear  transit  or  of  decisive  influence.  The 
weather  during  such  intervals  and  in  the  re- 
gions affected  might  be  defined  as  purely  local. 
It  takes  more  than  usual  the  impression  of 
strictly  local  conditions,  and,  except  as  in- 
fluenced by  these,  is  simply  a  matter  of  the  air 
warming  and  cooling  under  the  daily  coming 
and  going  of  the  sun.  But  whether  of  this  local 
type  or  of  the  more  general,  the  cyclonic,  it  has 
always  beneath  and  about  it,  as  the  ground  and 
limit  of  its  activity,  the  alternation  of  the 
seasons. 

Strictly,  there  are  but  two  seasons  in  any 

quarter  of  the  world — that  established  by  the 

sun's  journey  northward  and  that  established 

by  its  journey  southward.     Even  in  the  tem- 

138 


WINTER  AND  SUMMER  WEATHER 

perate  zones  it  is  somewhat  in  disregard  of  the 
sun  that  the  year  is  divided  into  four  seasons. 
When,  on  the  2ist  of  December,  the  sun,  turn- 
ing northward,  begins  its  summer  course,  the 
first  of  what  we  know  as  the  three  winter 
months — December,  January,  and  February — 
is  not  yet  ended.  The  first  of  the  three  summer 
months — June,  July,  and  August — is  also  not 
yet  ended  when,  on  June  2ist,  the  sun  turns 
southward  and  begins  its  winter  course. 

This  disparity  between  our  distribution  of 
the  seasons  and  the  sun's  actual  position  toward 
us  is  heightened  by  the  fact  that  all  of  the  sun's 
effects  on  the  temperature  come  and  go,  not 
exactly  with  the  sun,  but  always  a  little  after  it. 
This  is  true  not  only  with  reference  to  the  year, 
but  also  with  reference  to  the  day.  The  warm- 
est part  of  the  day  is  not  at  noon,  when  the  sun 
is  directly  overhead,  but  at  about  two  o'clock 
of  the  afternoon ;  and  the  coldest  part  is  not  at 
midnight,  when  the  sun  is  at  its  greatest  daily 
departure,  but  at  about  four  o'clock  in  the 
morning.  Of  the  year  the  warmest  part  is  the 
month  of  July,  when  the  sun  is  already  leaving 
us;  and  the  coldest  is  the  month  of  January, 
when  the  sun  is  already  coming  toward  us. 

There  is  no  part  of  the  United  States  in  which 
10  139 


OUR   OWN    WEATHER 

January  is  not  the  coldest  month.  There  are 
individual  weather  stations  whose  records  show 
now  December  and  now  February  as  colder 
than  January.  But  they  are  scattered  and  do 
not  represent  what  would  be  regarded  as  a 
section  or  region.  January  is  the  coldest 
month,  not  only  in  its  average  temperature, 
but  also  in  its  particular  records.  The  abso- 
lutely coldest  weather  recorded  in  the  course 
of  a  number  of  years  is  in  practically  every 
part  of  the  country  January  weather.  Every 
month  has  its  record  of  abnormally  cool  or  cold 
weather;  but  in  any  given  region  the  record  of 
no  other  month  is  as  low  as  the  record  for 
January.  Every  month  has  its  record  of  abnor- 
mally warm  weather;  but  in  any  given  region 
the  wannest  weather  of  January  is  colder  than 
the  warmest  weather  of  any  other  month. 
The  only  concession  to  other  months  which 
January  can  be  said  to  make  in  the  quality  of 
coldness  is  that  at  the  greatest  warmth  of 
which  it  is  capable  it  is  not  near  as  cold  as  the 
coldest  of  which  some  other  months  are  capable. 
The  lowest  cold  of  February,  for  example,  is  in 
any  one  region  much  colder  than  the  highest 
warmth  of  January. 

While  January  holds  its  place  as  the  leading 
140 


WINTER  AND  SUMMER  WEATHER 

winter-weather  month  without  any  but  the 
most  local  question,  it  has  always  a  close  com- 
petitor in  February.  The  difference  between 
them  in  general  temperature  is  small,  and  the 
severest  winter  weather  is  apt  to  fall  somewhere 
between  the  2oth  of  January  and  the  loth  of 
February.  Even  when  January  proves  un- 
seasonably mild — as  every  few  years,  though 
each  time  much  to  our  wonder,  it  does — it 
rarely  fails  toward  the  latter  end  to  recover 
enough  of  its  more  familiar  character  to  make 
us  remark  that  we  are  getting  some  winter  after 
all. 

The  severity  at  the  end  of  January  usually 
carries  over  into  February.  And  even  after  the 
first  third  of  February  there  is  almost  every 
year  weather  severe  enough  to  make  the  month, 
to  our  feeling,  quite  as  bad,  on  the  whole,  as 
January.  This  is  partly  because  we  have  then 
had  of  winter  quite  enough,  and  our  endurance 
begins  to  weaken.  But  in  part  it  is  also  be- 
cause in  the  latter  part  of  February  we  get  the 
first  of  those  sudden,  harsh  changes  of  weather 
that  always  mark  the  departure  of  winter  and 
exhibit  the  process  to  us  in  its  true  character, 
that  of  a  breaking-up.  About  as  many  cyclones 
cross  the  country  in  February  as  in  January, 
141 


OUR   OWN    WEATHER 

and  they  come  from  all  the  points  possible  at 
any  season,  except  from  the  West  Indies,  and  so 
bend  their  courses  as  to  weave  over  the  country 
a  closer  network  than  in  any  other  month. 

The  same  complete  pre-eminence  shown  by 
the  month  of  January  in  coldness  is  shown  by 
the  month  of  July  in  warmth.  July  is  the 
warmest  month  of  the  year  in  all  parts  of  the 
country,  not  only  in  its  ordinary  temperature, 
but  also  in  all  its  departures  from  the  ordinary. 
In  warmth,  as  in  coldness,  individual  stations 
show  some  variation  from  the  rule,  but  sec- 
tions or  regions  show  none.  North  and  south, 
east  and  west,  along  the  coasts  and  in  the 
interior,  July  is  almost  invariably  the  warmest 
month,  as  January  almost  invariably  is  the 
coldest. 

The  Distribution  of  January  Weather 

There  is,  however,  a  very  important  differ- 
ence between  the  distribution  of  the  cold  of 
January  and  that  of  the  warmth  of  July  among 
the  different  sections  of  the  country.  In  the 
central  section  ordinary  January  weather  is 
55  degrees  colder  on  the  northern  border  than 
on  the  southern.  In  the  northeast  corner  of 
142 


WINTER  AND  SUMMER  WEATHER 

North  Dakota  and  the  northwest  corner  of 
Minnesota,  which  constitute  the  coldest  region 
in  all  the  country,  the  normal  January  tempera- 
ture is  zero.  Follow  from  there  a  perfectly 
straight  line  south  and  the  ordinary  January 
weather  grows  steadily  and  rapidly  warmer 
until,  in  the  southernmost  corner  of  Texas,  the 
normal  January  temperature  becomes  55  de- 
grees above  zero. 

Start  at  any  point  in  this  line,  whether  in  its 
northern,  its  middle,  or  its  southern  section, 
and  go  straight  east,  and  again  January  weather 
grows  warmer  steadily,  but  now  not  rapidly, 
until  on  the  Atlantic  coast  it  shows  as  about 
1 5  degrees  warmer  than  at  the  point  of  starting. 
The  normal  January  temperature  for  northern 
Maine  is  15  degrees  above  zero,  or  15  degrees 
warmer  than  that  of  the  cold  corners  of  North 
Dakota  and  Minnesota.  For  the  southern- 
most part  of  Florida  the  normal  is  70  degrees 
above  zero,  or  15  degrees  warmer  than  that  of 
southernmost  Texas.  The  northern  (or  Maine) 
end  of  the  Atlantic  coast  is,  therefore,  exactly 
as  much  colder  in  ordinary  January  weather 
than  the  southern  (or  Florida)  end  as  northwest 
Minnesota  is  colder  than  southern  Texas — 
namely,  55  degrees. 


OUR   OWN    WEATHER 

Going  west  from  the  central  line,  we  find  the 
distribution  of  January  temperature  considerably 
less  regular  than  toward  the  east.  Here  also 
it  grows  gradually  warmer  in  the  direction  of  the 
sea.  But  the  Rocky  Mountains  produce  dis- 
turbance, and  the  increase  of  warmth  seaward 
is  not  along  the  straight  lines  which  so  distin- 
guish it  in  the  east.  Through  the  northern  tier 
of  states  it  is  quite  as  regular  as  anywhere. 
Eastern  Montana  is  5  degrees  warmer  than  the 
zero  region  in  North  Dakota;  and  western 
Montana  is  15  degrees,  Idaho  20  degrees, 
eastern  Washington  25  degrees,  and  Washington 
at  the  Pacific  coast  40  degrees  warmer  than  that 
region.  The  increase  westward  is  still  fairly 
regular  through  South  Dakota,  Wyoming, 
southern  Idaho,  and  Oregon.  But  through 
western  Kansas,  Colorado,  Utah,  and  Nevada 
no  increase  westward  is  shown. 

As  it  culminates  at  the  seacoast  the  increase 
westward  is  quite  a  bit  greater  than  the  increase 
eastward.  Southern  South  Carolina  and  north- 
ern Georgia  have  a  normal  January  temperature 
of  fifty  degrees,  the  same  as  that  of  southern 
California,  which  is  in  the  same  latitude.  But 
immediately  north  of  this  the  Atlantic  coast 
becomes  5  degrees  colder  for  January  than  the 
144 


5  3 

"*'  E- 


WINTER  AND  SUMMER  WEATHER 

corresponding  part  of  the  Pacific  coast;  and 
the  difference  between  them,  latitude  for  lati- 
tude, grows  steadily  greater  the  farther  north 
we  go  until,  in  contrast  with  a  normal  January 
temperature  in  Maine  of  only  15  degrees  above 
zero,  is  found  on  the  Pacific  coast  in  the  state  of 
Washington  a  normal  January  temperature  of 
40  degrees  above  zero. 

Instead  of  a  range  of  55  degrees  shown  on  the 
Atlantic  coast  between  the  north  end  and  the 
south  end,  the  Pacific  coast  shows  a  range  of 
only  10  degrees.  From  the  southern  boundary 
of  California  northward  two-thirds  of  the  way 
to  Oregon  the  normal  January  temperature 
along  the  coast  is  continuously  50  degrees  above 
zero.  On  from  that  point  to  a  little  north  of 
the  southern  boundary  of  Oregon  it  is  con- 
tinuously 45  degrees.  Then  for  the  rest  of 
the  way  to  the  Canadian  border  it  is  40  de- 
grees. 

The  reason  for  such  evenly  distributed  mid- 
winter warmth  is  not  far  to  seek.  The  east- 
ward movement  of  the  general  atmosphere 
brings  a  constant  supply  of  warm  air  from  the 
slow-cooling  ocean  in  to  the  coast.  It  is  only, 
though,  a  comparatively  narrow  border  that 
enjoys  this  tempering  influence.  The  air  sweeps 
H5 


OUR   OWN    WEATHER 

on  eastward  under  the  general  movement  and 
soon  begins  to  lose  its  warmth  by  contact  with 
the  winter-cooled  mountains.  It  descends  the 
eastern  front  of  the  Rocky  Mountains  with  its 
gracious  ocean  quality  about  all  gone.  There 
it  begins  at  once  to  mingle  with  air  yet  harsher 
that  is  pushing  down  from  the  great  heaps  of 
cold  air  which  the  winter  has  piled  up  over  the 
continent  in  the  north.  The  result  is  an  increas- 
ing coldness  of  the  air  until  the  central  line — the 
line  from  North  Dakota  to  Texas — is  reached. 
Here,  however,  air  drawn  from  the  southeast  and 
south  and  a  lessened  coldness  in  the  surface  of 
the  land  begin  to  be  effective,  and  there  sets  in 
that  eastward  warming  up  already  mentioned  as 
continuous  from  the  central  line  to  the  Atlantic 
coast. 

On  the  Atlantic  coast,  as  on  the  Pacific,  it  is 
mainly  the  influence  of  the  ocean  that  modifies 
the  winter.  But  on  the  Atlantic  side  of  the 
country  air  from  the  ocean  has  a  much  harder 
time  getting  in  than  on  the  Pacific  side.  The 
whole  year  through  it  has  against  it  the  east- 
ward movement  of  the  general  atmosphere. 
Except  during  the  warm  part  of  the  day  in 
summer  it  has  also  against  it  a  constant  pressure 
seaward  of  air  from  over  the  land,  due  to  the 
146 


WINTER  AND  SUMMER  WEATHER 

greater  coldness  and  density  of  such  air  in 
comparison  with  air  from  over  the  water. 

Normally,  along  the  Atlantic  and  Gulf  coasts 
breezes  from  the  sea  are  an  affair  only  of  the 
summer,  and  then  only  of  the  daytime.  But 
the  rule  gets  broken  every  few  days  by  the  pas- 
sage of  cyclones.  These,  as  we  have  seen,  are 
particularly  frequent  and  particularly  strong  in 
winter,  and,  since  by  their  rotating,  upward 
draft  they  suck  the  air  in  from  all  directions, 
they  draw  in  enough  from  the  direction  of  the 
sea  to  modify  somewhat  the  winter  throughout 
the  eastern  and  southeastern  regions. 

Commonly  for  the  lessened  severity  of  winter 
along  the  Atlantic  coast  all  credit  is  given  to  the 
Gulf  Stream — that  current  continually  flowing 
out  of  the  Gulf  of  Mexico  between  Florida  and 
Cuba  into  the  main  body  of  the  Atlantic  and 
then  northward  and  eastward,  and  keeping  for 
a  long  distance  a  color  and  speed,  as  well  as 
warmth,  in  clearly  marked  contrast  with  those 
of  the  surrounding  ocean.  But  the  persons 
whose  opinion  in  such  a  matter  is  of  any  au- 
thority are  pretty  well  agreed  that,  except 
somewhat  along  the  shores  of  North  and  South 
Carolina,  Georgia,  and  Florida,  the  Gulf  Stream 
is  with  us  of  next  to  no  effect.  Down  to  the 
H7 


OUR   OWN   WEATHER 

middle  of  North  Carolina  the  water  that 
washes  the  Atlantic  coast  is  a  stream  from  the 
north,  a  cold  stream,  known  as  the  Labrador 
current.  Even,  though,  without  the  special 
warmth  of  the  Gulf  Stream  to  temper  it  any 
air  that  comes  to  us  in  winter  from  off  the 
Atlantic  will  be  warmer  than  the  air  coming 
then  from  the  Rocky  Mountains. 

The  Distribution  of  July  Weather 

In  July,  instead  of  a  difference  of  55  degrees, 
as  in  January,  between  the  northern  and  the 
southern  borders  of  the  country  in  ordinary 
temperature,  there  is  a  difference  of  only  20 
degrees.  Between  no  one  part  of  the  country 
and  any  other  is  the  difference  more  than  this. 
Between  the  central  region,  extending  from 
North  Dakota  to  Texas  and  any  of  the  country 
east  of  that,  there  is,  latitude  for  latitude, 
almost  no  difference.  At  the  north  the  normal 
July  temperature  is  65  degrees  above  zero; 
at  the  south  it  is  from  8 1  to  82.  The  Atlantic 
coast  is,  though,  on  the  whole,  a  little  the  cooler 
part. 

Westward  the  Rocky  Mountains  again  pro- 
voke, as  in  January,  considerable  irregularities. 
148 


WINTER  AND  SUMMER  WEATHER 

Through  southeastern  Montana  and  southward 
through  Wyoming,  Colorado,  and  northern  New 
Mexico,  then  northwestward  through  northern 
Utah  and  northern  Nevada  and,  finally,  through 
most  of  the  length  of  California,  a  little  back 
from  the  coast,  the  ordinary  July  temperature 
is  70  degrees  above  zero.  And  this  is  the  same 
as  that  of  South  Dakota,  southern  Minnesota, 
Wisconsin,  southern  Michigan,  central  New 
York,  and  central  New  England.  Just  along 
the  Pacific  coast  from  Los  Angeles  north  to  the 
Canadian  border  the  July  normal  is  continu- 
ously 65  degrees  above  zero,  and  this  is  the 
same  as  that  of  the  Maine  coast.  On  the 
coast  of  North  and  South  Carolina  the  normal 
is  80.  The  very  hottest  part  of  the  country 
is  the  southeast  corner  of  California  and  the 
southwest  corner  of  Arizona,  with  an  ordi- 
nary July  temperature  of  85  degrees  above 
zero. 

A  difference  in  normal  temperature  of  never 
more  than  twenty  degrees  between  the  several 
sections  of  a  territory  so  vast  and  so  multiform 
marks  an  evenness  of  atmospheric  conditions 
that  is  extremely  placating  to  the  weather.  In 
midsummer  the  weather  tends  always  to  be 
stable  and  even  stagnant.  It  is  cool  or  hot, 
149 


OUR   OWN    WEATHER 

according  to  latitude,  but  is  little  subject  to 
sharp  changes.  The  average  departures  from 
normal  temperature  are  not  half  as  great  as  in 
midwinter.  Areas  of  air  of  low  pressure  arise 
and  traverse  the  country  with  little  less  fre- 
quency in  summer  than  in  winter.  But  they 
are  for  the  most  part  mild  organizations, 
scarcely  deserving  the  name  of  cyclones  and 
keeping  in  their  slow  travels  pretty  close  to  the 
northern  border.  Their  most  marked  effect  is 
to  produce  the  local  disparities  of  temperature 
that  result  in  thunder-storms  and  tornadoes. 
Since  these  are  always  sharp  and  often  destruc- 
tive, the  storminess  of  summer  keeps  us  more 
in  fear  than  the  storminess  of  winter,  but  it  is 
immeasurably  less  both  in  the  time  covered  and 
in  the  total  force  raised  and  expended.  Almost 
everywhere  there  is  less  cloudiness  in  summer 
than  in  winter,  and  the  summer  winds  are  much 
weaker  than  those  of  winter.  Over  the  Western 
plains  there  is  much  more  rainfall  in  summer 
than  in  winter,  and  in  several  other  parts  of 
the  country  there  is  in  summer  rather  more 
than  in  winter.  But  in  the  rainiest  part  of  all, 
the  north  Pacific  coast,  there  is  next  to  no  rain 
in  summer. 


WINTER  AND  SUMMER  WEATHER 
The  Passage  from  Winter  into  Summer 

After  January  in  any  part  of  the  country  each 
month  is  warmer  than  the  month  just  before  it 
up  to  and  including  July;  and  after  July  each 
month  is  colder  than  the  month  just  before  it 
up  to  and  including  January.  In  view  of  this 
fairly  close  parallel  we  might  expect  the  two 
seasons  of  transition,  spring  and  autumn,  to  be 
much  alike.  They  are,  in  fact,  though,  quite 
different. 

The  passage  from  winter  into  summer  is  a 
much  more  halting  and  disturbed  passage  than 
that  from  summer  into  winter.  The  first  of 
the  spring  months,  March,  hardly  ever  comes 
round  that  we  don't  deride  and  objurgate  it  for 
having  got  itself  called  a  spring  month.  And 
April,  as  offering  what  we  are  willing  to  accept 
as  spring,  has  with  us  scarcely  better  standing 
than  March.  We  often  mock  also  at  what 
seem  to  be  the  unfounded  pretensions  of  the 
first  of  the  autumn  months,  September.  But 
September  is  passive :  its  offense  is  nothing  but 
a  refusal  to  change.  It  stays  as  hot  and  humid 
as  August.  In  March  change,  and  harsh  change, 
is  the  almost  daily  order.  Bodies  of  very  cold 
air  from  the  north  and  bodies  of  warm  air  from 


OUR   OWN    WEATHER 

the  south  are  in  a  constant  battle.  Now  for  a 
few  days  one  controls  the  field,  and  now  for  a 
few  days  the  other,  according  to  the  usual 
fortunes  of  war. 

The  nature  of  the  conflict  is  shown  rather 
clearly  in  the  character  and  courses  of  the 
cyclones.  These  are  about  as  numerous  in 
March  as  in  any  of  the  winter  months.  But  a 
somewhat  less  number  of  them  than  in  January 
or  February  are  from  the  southwest,  a  sign  that 
spring  begins  to  be  already  established  there. 
Those  from  the  northwest,  on  the  other  hand, 
are  more  frequent  than  in  any  other  month, 
and,  more  unfailingly  and  farther  than  in  any 
other  month,  they  loop  down  into  the  south. 
This  shows  them  to  be  under  a  very  strong 
push  from  the  cold  masses  of  air  on  the  lower 
borders  of  which  they  form.  They  are  at 
the  same  time  eagerly  set  upon  by  air  of 
full  spring  warmth  from  the  south.  The  con- 
test between  bodies  of  warm  and  bodies  of 
cold  air  thus  becomes  extreme,  and  the  main 
form  of  it  is  a  conflict  of  winds.  It  continues 
with  little  or  no  abatement — often  even  with 
increase — as  the  cyclones,  having  turned  north- 
eastward, pursue  their  long  course  to  the  St. 
Lawrence  valley.  Poor  March,  in  consequence, 
152 


WINTER  AND  SUMMER  WEATHER 

has  to  bear  the  odium  of  being  the  squalliest, 
windiest  month  of  all  the  year.  We  might, 
perhaps,  have  less  discomfort  in  her  presence 
than  we  commonly  do  if  we  remembered  oftener 
what  a  truly  magnificent  business  it  is  over 
which  she  presides. 

The  conflict  so  sharp  in  March  continues 
through  a  good  part  of  April.  But  it  modifies 
from  a  succession  of  grim,  boisterous,  open  fights 
into  a  sort  of  chuckling,  impish  guerilla  warfare. 
There  begins  to  be  a  pretty  wide  distribution 
of  air  that  is  both  warmer  and  moister  than  the 
air  of  winter.  It  is,  though,  what  might  be 
called  a  spotty  distribution — a  little  here  and  a 
little  there — and  offers  fine  ground  for  smart, 
little,  unlooked-for  outbursts  of  weather.  The 
cyclones  are  fewer  and  keep  to  straighter 
courses,  making  fewer  and  shorter  loops  into 
the  south,  than  in  March  or  in  any  of  the  winter 
months.  They  still  have  considerably  more 
strength  than  they  show  in  summer,  but  are 
apt  to  provoke  by  their  passage  disturbances 
confined  to  relatively  small  areas.  April  has 
come  to  be  known  to  us  in  its  weather,  there- 
fore, as  the  embodiment  of  all  fitfulness.  Now 
fair,  now  cloudy,  now  warm  and  friendly,  now 
cold  and  repellant,  we  yield  it  our  love,  but 


OUR   OWN    WEATHER 

never  our  confidence.  It  is  known  especially 
to  us  as  the  showery  month. 

The  advance  of  spring  is  rather  from  the 
southwest  than  just  from  the  south,  and  has 
something  of  an  eastward  as  well  as  a  north- 
ward course.  It  is  not  a  steady  advance,  as 
the  weather  peculiar  to  March  and  April  clearly 
shows.  It  is  a  succession  of  pushes  forward 
only  to  be  driven  back  that  net  each  time  some 
gain,  until  finally  the  whole  field  is  won  and 
placed  under  the  full  dominion  of  summer.  Of 
the  turns  and  time  involved  in  the  movement 
we  can  get  some  idea  from  the  fact  that  May  in 
central  Massachusetts  is,  in  its  average  warmth, 
six  degrees  colder  than  May  in  central  Ohio,  and 
just  the  same  as  March  in  central  Alabama, 
and  nearly  the  same  as  March  in  central  Texas, 
and  as  February  in  southern  Arizona.  It  is,  on 
the  whole,  to  New  England  and  to  the  country 
around  the  upper  part  of  the  Great  Lakes  that 
spring  comes  last.  Its  lateness  in  the  latter 
region  is  imputed,  in  part,  to  the  slow  warming- 
up  of  the  water  of  the  Lakes. 

Winter  and  summer,  once  established,  hold 
through  a  good  part  of  their  terms  without 
much  change.  Between  the  several  months  of 
either  season  the  difference  in  average  tempera- 


WINTER   AND  SUMMER  WEATHER 

ture  is  small.  This  is  the  case  in  all  parts  of 
the  country.  While  January  is  always  the 
coldest  month,  it  is,  on  an  average,  only  from 
four  to  five  degrees  colder  than  December  and 
only  from  one  to  two  degrees  colder  than  Febru- 
ary. Likewise,  July,  while  always  the  warmest 
month,  is,  on  an  average,  only  from  four  to  five 
degrees  warmer  than  June  and  only  from  one  to 
two  degrees  warmer  than  August. 

But  between  the  months  of  transition, 
whether  spring  or  autumn,  the  difference  is 
much  greater.  On  an  average  March  is  from 
eight  to  nine  degrees  warmer  than  February, 
April  from  twelve  to  thirteen  degrees  warmer 
than  March,  May  from  eleven  to  twelve  degrees 
warmer  than  April,  June  from  eight  to  nine  de- 
grees warmer  than  May.  The  average  differ- 
ences in  autumn  are  practically  the  same.  On 
an  average  September  is  colder  than  August  by 
from  eight  to  nine  degrees,  October  colder  than 
September  by  from  eleven  to  twelve,  November 
colder  than  October  by  from  twelve  to  thirteen, 
and  December  colder  than  November  by  from 
eight  to  nine  degrees. 

While  the  changes  of  autumn  closely  offset, 
as  in  the  nature  of  things  they  must,  the  changes 
of  spring,  the  autumn  transition  is,  in  compari- 


OUR   OWN    WEATHER 

son  with  that  of  spring,  a  very  equable  affair. 
There  is  an  increasing  number  of  cyclones, 
with  an  increasing  closeness  of  organization. 
But  they  travel  pretty  generally  along  the 
northern  border  and  produce  comparatively 
little  rain.  It  is  the  season  of  West  Indian 
hurricanes,  and  of  those  that  come  to  us  the 
harder  ones  show  something  of  preference  for 
the  latter  part  of  September.  This,  more  than 
any  sudden  starting  up  of  cyclones  from  the 
northwest,  has  fixed  us  in  the  habit  of  expect- 
ing about  September  2ist,  when  the  sun  in  its 
journey  south  crosses  the  equator,  what  we  call 
the  equinoctial  storm.  The  expectation  is 
realized  only  just  enough  to  keep  it  from  year 
to  year  well  alive.  Such  storms  as  come  then  or 
later,  until  near  the  end  of  November,  are  apt 
to  be  clean,  straight-out  affairs  that,  either  of 
their  presence  or  of  their  departure,  leave  us 
in  no  disgusting  doubt.  Of  sharply  variable, 
truly  turbulent  weather  there  is  next  to  none 
until  autumn  is  nearly  or  wholly  past.  Even 
the  first  good  snowfall,  which  we  who  live 
within  the  snow  -  zone  think  it  quite  against 
nature  not  to  have  at  or  near  Thanksgiving, 
often  comes  considerably  after  its  date. 

Pretty  regularly  the  cyclones  are  followed  by 
156 


WINTER  AND  SUMMER  WEATHER 

anticyclones  that  keep  the  whole  country  suf- 
fused often  for  as  much  as  a  week  or  ten 
days  at  a  time  with  cool,  dry  air  that  puts 
us  all  into  the  finest  feeling.  Under  the  ex- 
hilaration of  this  we  think  each  year  that 
we  never  knew  before  at  that  season  such 
beautiful  weather.  But  it  conies  just  as  fair 
and  quickening  practically  every  autumn.  It 
was  the  definiteness  and  sure  recurrence  of  it 
that  long  ago  caused  the  period  of  it  to  be 
marked  by  a  special  name,  that  of  Indian  sum- 
mer. Under  the  prevailing  dryness  dust  from 
roads  and  plowed  fields  and  from  the  break- 
ing up  of  fallen  foliage,  along  with  smoke  from 
forest  fires,  which  are  then  most  frequent,  rises 
into  the  lower  air  and,  in  the  absence  of  strong 
winds,  lingers  there.  And  this  makes  the 
familiar  Indian-summer  haze.  Haze  as  deep  and 
as  enduring  may  occur  at  other  times  in  the 
year;  and  even  in  Indian  summer  haze  is  not 
quite  unfailing.  But  an  Indian  summer  with- 
out it  puts  us  always  to  the  question  whether, 
this  year,  we  are  not  missing  our  Indian  summer. 
Spring,  perhaps,  has  enjoyed  more  of  the 
honors  of  poetry  than  autumn  has.  That  is 
due  in  part  to  the  fact  that  most  of  the  earlier 
poetry  was  written  in  climates  different  from 


OUR   OWN    WEATHER 

ours,  and  we  have  taken  over  many  of  its  ideas 
and  phrases  without  too  much  thinking.  But 
it  is  due  in  part  also  to  the  fact  that  spring, 
in  spite  of  its  fickleness — or,  possibly,  because 
of  that — does  fill  the  heart  and  the  world  with 
hope.  Autumn  does  not  exactly  repress  or 
expel  hope,  but  it  is  at  least  somewhat  sobering 
and  subduing.  The  officials  of  the  Weather 
Bureau  ought  not,  though,  to  feel  it  so,  for  on 
account  of  its  evenness  and  regularity  they  find 
it,  they  say,  the  easiest  season  of  all  the  year  in 
which  to  forecast  the  weather.  That  the  public 
at  large,  however,  has  detected  in  their  pre- 
dictions for  autumn  a  superior  felicity  over 
those  of  other  seasons  I  rather  doubt.  In  any 
craft  it  is  only  the  devotees  who  know  its  nicer 
joys. 


HOT  AND  COLD  WAVES,  AND  OTHER  EXCESSES 
OF  THE  SEASONS 

THE  seasons  maintain,  if  not  through  the 
year,  certainly  through  the  years,  a  notable 
fidelity  to  their  times,  and  as  notable  a  uniform- 
ity in  their  effects.  But,  like  all  nature,  human 
and  other,  they  reward  their  virtue  now  and 
then  by  running  into  excesses.  Of  these,  most 
familiar,  perhaps,  are  the  cold  waves  of  winter 
and  the  hot  waves  of  summer.  In  neither  the 
one  nor  the  other  is  there  any  departure  from 
the  ordinary  course  of  things,  but  only  a  pursuit 
of  that  course  with  for  the  moment  more  than 
ordinary  zeal.  Cyclones  and  anticyclones  are 
still  the  immediate  masters  of  the  weather  even 
when  it  breaks  into  these  seemingly  freakish 
forms. 

The  Cold  Wave 

A  cyclone  not  essentially  different  from  those 
that  are  all  the  time  forming  and  moving  off 


OUR   OWN    WEATHER 

across  the  country  gets  established  somewhere 
along  the  eastern  front  of  the  Rocky  Mountains. 
Close  behind  it  is  an  anticyclone  of  extreme 
coldness.  This  comes  oftenest  in  through 
Montana,  and  can  usually  be  traced  back  to 
some  point  considerably  north  of  there.  Most 
frequently  it  attracts  observation  by  its  special 
quality  first  in  the  region  of  the  Klondike,  and 
has  sometimes  been  under  surveillance  for  two 
or  three  weeks  before  it  crosses  our  border. 
How  far  its  exceptional  coldness  is  due  simply 
to  the  northerliness  of  its  place  of  starting,  and 
how  far  to  a  particular  state  of  the  higher  atmos- 
phere from  which  much  of  the  air  it  dispenses 
is  drawn  down,  remains  quite  undetermined. 
We  can  say  with  certainty  of  it  only  that  here 
it  is,  and  that  it  is  extraordinarily  cold. 

The  cyclone,  choosing  one  or  another  of  the 
wonted  paths,  goes  its  way.  It  draws  into  the 
front  of  it,  like  any  other  cyclone,  relatively 
warm  air  from  the  east  and  south.  But  at  the 
rear  it  draws  into  it,  or  rather  has  driven  into 
it,  from  the  close-following  anticyclone  air 
much  colder  than  is  usual  even  from  the  cold 
quarter.  Thus  there  is  built  up  between  its 
warm  southeast  and  its  cold  northwest  quarter 
a  difference  of  temperature  much  beyond  the 
1 60 


HOT    AND   COLD   WAVES 

ordinary.  The  difference  may  amount  to  more 
than  forty  degrees.  It  is  bestowed  without 
reserve  upon  all  the  localities  that  the  cyclone 
visits.  To-day  they  will  have  mild,  warming 
breezes  from  the  east  or  south,  with,  probably, 
rain.  To-morrow  the  rain,  perhaps,  has  turned 
into  snow  and  the  breezes  have  become  a  west 
or  northwest  blast,  driving  cold  into  the  very 
marrow  of  man  and  beast. 

If  the  cyclone  bends  its  course  far  into  the 
south  the  cold  wave  spreads  over  the  whole 
country  east  of  the  Rocky  Mountains.  But  if 
it  keeps  well  up  in  its  course  the  northern  half 
of  the  country  may  experience  a  perfectly 
cruel  change  of  which  the  southern  half  gets 
scarcely  a  touch.  West  of  the  Rocky  Moun- 
tains the  effect  of  cold  waves  coming  in  through 
Montana  is  less  clear  and  positive  than  to  the 
east.  But  they  do  often  have  a  western  spread. 
The  great  diversity  of  altitude  and  exposure 
throughout  the  Plateau  and  Pacific  slope  region 
makes  abrupt  changes  of  temperature  more 
common  there  than  in  any  other  part  of  the 
country,  but  also  more  confined  and  local. 
Yet  many  of  the  sharp  descents  of  cold  come 
unmistakably  from  the  east  and  north.  Occa- 
sionally they  traverse  the  entire  region,  running 
161 


OUR   OWN    WEATHER 

even  to  the  southern  border  of  California  and 
producing  unquestionable  ice  at  San  Diego, 
where  the  ordinary  winter  temperature  is 
twenty-three  degrees  above  freezing.  The 
very  rarity  of  such  invasions  makes  them 
extremely  damaging. 

There  are  winter  anticyclones  coming  in 
through  Washington  and  Oregon  from  off  the 
Pacific.  At  starting  they  are  relatively  warm 
and  also  moist.  They  become  colder  in  crossing 
the  mountains,  and  shed  their  excess  of  mois- 
ture, often  in  the  form  of  snow.  They  some- 
times produce  snow  not  only  on  the  western, 
but  also  on  the  eastern  slope.  Occasionally 
one  of  them,  having  passed  the  mountains,  en- 
counters a  trough  of  warm,  moist  air  lying 
stretched  out  northeast  and  southwest  between 
Arizona  and  the  Great  Lakes  and  cuts  it  quite 
in  two.  The  southern  fragment  thereupon 
rounds  up  into  an  active  cyclone;  and  under 
the  further  career  of  it  and  the  anticyclone 
heavy  snows  and  considerably  colder  weather 
are  produced  over  most  of  the  country  eastward. 

Very  sudden  cold  waves  are  brought  to  us 

only  on  the  western  skirts  of  a  cyclone.     If  in 

addition  to  being  very  sudden  they  are  also 

very  strong,  there  is  sure  to  be  close  behind  the 

162 


HOT   AND   COLD    WAVES 

cyclone  an  anticyclone  of  extreme  coldness. 
But  those  quite  as  sudden,  though  perhaps 
never  so  strong,  may  arise  from  a  cyclone's 
drawing  into  it,  not  abnormally  cold  air  at  the 
rear,  but  abnormally  warm  air  at  the  front. 
In  such  a  case,  the  eastern  quarters  being  ex- 
cessively warm,  the  western  quarters  need 
not  be  excessively  cold  to  make  the  change 
of  temperature  under  the  cyclone's  passage 
still  sharp. 

Cold  waves  coming  in  either  of  these  two 
ways  are  apt  to  be  brief.  With  any  one  of 
them  three  days  will  usually  see  it  all  come  and 
gone.  They  are  also  quite  sure  to  be  attended 
by  high  winds.  It  is  under  the  advance  of  the 
severer  ones  that  we  get  that  for  which  we 
have  coined  the  expressive  name  of  blizzard. 
Under  the  ruthless  drive  of  the  wind  a  storm 
beginning  perhaps  in  rain,  but  turning  first 
into  sleet  and  then  into  snow,  becomes  so 
bewildering  and  exhausting  that  often  men 
and  animals  simply  sink  down  before  it  and 
perish  in  the  magically  risen  drifts.  This 
feature  of  it  is  what  makes  the  cold  wave 
especially  harmful  throughout  the  northern 
half  of  the  region  between  the  Mississippi 
River  and  the  Rocky  Mountains. 
163 


OUR   OWN    WEATHER 

A  cold  anticyclone  often  produces  a  cold 
wave  more  by  its  presence  than  by  its  progress. 
The  cold  wave  is  established,  not  at  the  point 
where  the  anticyclone  is  pouring  its  cold  air 
into  a  preceding  cyclone,  but  in  the  central 
region  of  the  anticyclone  and  westward  from 
there.  The  anticyclone,  being  itself  very  cold, 
simply  imparts  its  temperature  to  the  country 
lying  just  under  it.  A  cold  wave  of  this  kind 
comes,  as  a  rule,  without  high  wind  and  gradu- 
ally. It  is  never  so  shocking  as  the  other  kind, 
but  it  may,  by  its  steady  piling  up,  become 
much  colder.  And  it  may,  if  the  anticyclone 
is  of  slow  movement,  as  anticyclones  often  are, 
continue  over  a  given  region  for  more  than  a 
week.  In  that  case  it  rather  exceeds  the  limits 
of  a  cold  wave  and  becomes  more  properly  a 
cold  term. 

Under  cold  waves  of  this  kind  there  may  be 
abundant  discomfort,  but  there  is  apt  to  be  no 
great  damage.  A  curious  and  interesting  fea- 
ture of  them  is  that  the  layer  of  clear,  cold  air 
which  they  spread  abroad  is  comparatively 
thin.  This  is  indicated  in  such  observations  as 
that,  for  example,  when  in  the  region  of  Helena, 
Montana,  the  temperature  was  from  twenty- 
five  to  thirty  degrees  below  zero,  on  levels  just 
164 


HOT   AND   COLD    WAVES 

beside  it,  but  about  three  thousand  feet  higher, 
the  temperature  was  above  freezing. 

Changes  of  the  kind  that  we  know  as  cold 
waves  may  occur  at  any  season.  But  it  is  only 
in  the  winter  half  of  the  year  that  they  carry 
the  temperature  from  warmth  down  into  posi- 
tive coldness.  To  give  the  phrase  a  working 
quality  the  Weather  Bureau  has,  so  to  say, 
"standardized"  the  cold  wave.  The  standard 
varies  somewhat  according  to  time  and  place. 
Along  the  Gulf  coast  there  must  be  to  consti- 
tute a  cold  wave  a  fall  in  temperature  within  a 
period  of  twenty-four  hours  of  at  least  sixteen 
degrees;  and  in  other  districts  there  must  be  a 
fall  of  at  least  twenty  degrees.  In  the  colder 
regions  the  fall  must  be  also  to  at  least  zero  in 
the  colder  months,  December,  January,  and 
February.  But  in  November  and  March  a 
fall  to  ten  above  zero  will  suffice.  Along  the 
Gulf  and  in  Florida  a  fall  at  any  time  to 
only  the  freezing-point  (thirty-two  degrees)  is 
enough. 

Of  cold  waves  that  fulfil  these  requirements 
there  are,  on  an  average,  three  or  four  a  year. 
They  are  about  as  likely  to  occur  in  one  as  in 
another  of  the  five  months  to  which  they  are 
confined,  except  that  they  are  rarest  in  Novem- 
165 


OUR    OWN    WEATHER 

her;  and  they  are  no  more  likely — are,  perhaps, 
less  likely — to  occur  in  prevailingly  cold  win- 
ters than  in  winters  marked  by  considerable 
stretches  of  mildness.  The  fall  of  temperature 
they  effect  is  sometimes  tremendous — more 
than  fifty  degrees  within  a  period  of  twenty- 
four  hours. 

The  Hot  Wave 

The  hot  wave  is  to  the  summer  season  exactly 
what  the  cold  wave  is  to  the  winter — a  brief, 
strong,  wide-sweeping  increase  of  the  season's 
natural  quality.  As  in  its  quality,  though,  so 
in  the  manner  of  its  production,  it  is  the  direct 
opposite  of  the  cold  wave.  While  the  latter  is 
always  bred  and  nourished  by  a  cold  anticyclone 
from  the  northwest,  the  hot  wave  gets  its  birth 
and  substance  always  from  a  hot  anticyclone 
in  the  southeast.  The  hot  anticyclone  is,  how- 
ever, deemed  to  be,  not  a  distinct  organization 
in  itself,  but  a  part  of  that  belt  of  air  of  high 
pressure  already  described  as  lying,  with  more 
or  less  permanence,  across  the  Atlantic  Ocean, 
and  as  having  much  to  do  with  the  rise  and 
behavior  of  West  Indian  hurricanes. 

At  a  time  when  this  belt  chances  to  be  rather 
farther  and  more  strongly  projected  than  ordi- 
166 


HOT    AND   COLD   WAVES 

narily  over  the  Southeastern  states  there  may 
arise  in  the  northwest  an  area  of  air  of  low  pres- 
sure which  has  close  behind  it  no  definite 
anticyclone  to  round  it  up  and  drive  it  forward. 
Itself  scantly  defined  and  sluggish,  it  lingers  in 
one  place.  It  is  still,  though,  of  low  enough 
pressure  to  be  an  attractive  object  to  the  air  of 
high  pressure  in  the  southeast.  This  begins, 
therefore,  to  stream  north  and  west.  It  is  hot 
at  starting,  and  it  cools  little  in  its  northward 
progress,  partly  because  it  travels  fast  and 
partly  because  everywhere  the  land  over  which 
it  flows  is  at  full,  or  nearly  full,  summer  warmth. 
It  thus  establishes  in  all  the  country  it  invades 
the  hottest  kind  of  .weather.  Its  effect  is  apt 
to  be  severest  through  the  Mississippi  and  the 
Ohio  valleys;  but  it  is  often  severe  enough  to 
be  rated  that  of  a  hot  wave  everywhere  between 
the  Rocky  Mountains  and  the  Atlantic  Ocean. 

Just  along  the  Atlantic  coast  the  effect  is 
usually,  though  not  unfailingly,  much  modified 
by  the  sea-breezes  prevalent  through  the  middle 
of  the  day  in  summer.  To  the  Pacific  coast 
the  strict  hot  wave  never  quite  reaches,  though 
periods  of  a  day  or  two  of  abnormal  heat 
sometimes  occur  there.  It  may  extend  into  and 
even  across  the  Rocky  Mountains.  But  the 
167 


OUR   OWN    WEATHER 

great  elevation  of  the  mountain  and  plateau 
regions  insures  to  them  a  rapid  radiation  and 
cooling  off  at  night,  and  the  hotness  of  the 
nights  as  well  as  of  the  days  enters  into  the 
definition  of  a  true  hot  wave. 

It  is  always,  indeed,  directly  in  proportion  as 
hot  nights  are  combined  with  hot  days  that 
hot  waves  prove  disastrous.  For  a  number  of 
days  successively  the  heat  may  mount  during 
the  day  to  extraordinary  heights;  but  if  the 
intervening  nights  turn  comparatively  cool  the 
number  of  prostrations  and  deaths  will  be  much 
less  than  under  a  considerably  lower  tempera- 
ture continuing  with  scant  abatement  through 
the  day  and  night.  Thus  any  situation  that 
peculiarly  favors  cooling  off  at  night  has  a  clear 
advantage  during  the  prevalence  of  a  hot  wave. 
It  is  also  an  advantage  to  be  inured  to  heat. 
The  same  degree  of  it  that  would  cause  great 
suffering  to  the  people  of  the  North  imposes 
nothing  more  than  discomfort  on  the  people 
of  the  South. 

The  South,  however,  is  the  region  in  which 
hot  waves  provoke  least  change.  Since  they 
start  there,  the  temperatures  they  carry  with 
them  are  but  those  already  more  or  less  prev- 
alent there.  The  severity  of  them  tends  to 
1 68 


HOT    AND   COLD    WAVES 

become  greater  and  greater  as  they  proceed 
northward,  until  finally  some  line  is  crossed 
where  they  themselves  begin  decidedly  to  cool. 
Thus,  in  one  of  the  most  fatal  hot  waves 
of  which  we  have  official  record  no  increase 
of  temperature  worth  mentioning  occurred 
at,  for  example,  either  Jacksonville,  Florida; 
Charleston,  South  Carolina;  or  New  Orleans. 
But  at  St.  Louis,  Chicago,  New  York,  and 
Boston  the  temperature  not  only  had  very 
strong  individual  rises,  but  also  maintained 
through  a  number  of  days  an  average  any- 
where from  thirteen  to  seventeen  degrees  above 
normal.  The  South,  therefore,  is  the  region  to 
which  we  should  repair  in  order  to  escape  not 
only  cold  waves,  but  also  hot  ones.  Its  own 
suffering  is,  on  the  whole,  more  from  the  former 
than  from  the  latter. 

The  conditions  that  are  necessary  to  a  hot 
wave  may  arise  at  any  season.  But  they  arise 
with  more  frequency  and  in  greater  strength 
in  summer  than  in  winter;  and  it  is,  of  course, 
only  in  summer  that  in  our  latitude  air  poured 
forth  from  any  quarter  is  truly  hot.  To  pro- 
voke a  hot  wave  there  must  be  somewhat  of  a 
pause  and  feebleness  in  the  movement  eastward 
of  cyclones  and  anticyclones  from  the  north- 
169 


OUR   OWN    WEATHER 

west.  This  in  summer  is  rather  the  ordinary 
character  of  the  movement,  but  in  winter  is 
exceptional  in  it.  For  strict  hot  waves  June, 
July,  August,  and  September  are  the  only 
months.  Of  the  four  June  is  the  least  liable  to 
them,  July  most;  but  August  and  September 
have  a  liability  not  much  less  than  that  of  July. 
Those  of  July  and  August  are  apt  to  be  severer 
than  those  of  September  and  June  because  they 
are  apt  to  be  both  hotter  and  dryer. 

Beyond  the  very  loose  one  of  confinement  to 
the  hotter  months  hot  waves  exhibit  no  regu- 
larity. They  may  come  strong  or  weak,  and  in 
close  succession  or  far  apart.  There  is  hardly, 
if  ever,  a  summer  without  one,  and  there  may 
be  in  a  single  summer  a  number  of  them — say, 
four  or  five.  They  are  not  necessarily  confined 
to  summers  that  are  prevailingly  hot,  nor  are 
they  necessarily  more  frequent  in  such  summers. 
The  highest  absolute  heat  produced  by  them  is 
apt  not  to  come  until  a  day  or  two  after  the 
arrival  of  the  wave  itself. 

Usually  a  hot  wave  is  dissipated  by  the  organ- 
ization and  movement  eastward  of  a  cyclone 
of  some  strength,  followed  by  an  anticyclone. 
But  it  may  simply  waste  away  under  a  shift 
or  withdrawal  eastward  of  the  Atlantic  belt 
170 


HOT    AND   COLD   WAVES 

of  high  pressure  out  of  which  it  is  fed.  The 
stagnation  of  the  ordinary  atmospheric  ex- 
changes in  which  alone  it  can  arise  is  apt, 
though,  to  be  itself  prolonged.  Under  such 
favoring  the  hot  wave  exceeds  its  ordinary 
limit,  which  is  three  or  four  days,  and  lengthens 
out  into  what  we  know  as  a  heated  term.  And 
since  in  the  weather  any  continued  warming 
up  is  bound  to  become  also  a  drying  up,  the 
lengthening  of  a  hot  wave  into  a  heated  term 
is  nearly  always  productive  of  a  drought.  It 
is,  therefore,  more  under  the  heated  term  than 
under  the  mere  hot  wave  that  we  discover  of 
what  severities  summer — somehow  always  more 
amiable  than  winter  to  us  in  its  general  associa- 
tions— is  really  capable. 

Mild  Seasons  and  Hard  Seasons 

Hot  waves  and  cold  waves,  even  when  they 
stretch  out  into  terms,  are  episodes.  But  the 
seasons  often  indulge  in  excesses  that  are 
season  long.  There  is  never  any  that  does  not 
have  its  irregularities,  its  abnormalities;  and 
within  any  period  of  a  few  years  there  is  sure 
to  come  one,  either  a  summer  or  a  winter,  so 
constant  in  them  that  its  whole  character  is 
12  171 


OUR   OWN    WEATHER 

abnormal.  It  shows,  in  comparison  with  an 
ordinary  season,  as  either  colder  or  warmer,  and 
at  the  same  time  as  either  wetter  or  dryer.  A 
hot  summer  and  a  cold  winter  are  also  dry.  A 
cold  summer  and  a  warm  winter,  on  the  other 
hand,  are  also  wet. 

They  come  with  no  discernible  regularity, 
these  entire  seasons  of  unusual  warmth  or  cold- 
ness. Mainly  out  of  personal  memory  of  them, 
which  is  apt  to  be  vague  and  inexact,  we  have 
framed  various  rules  for  them ;  and  these  we  cite, 
if  not  with  great  confidence,  certainly  with 
great  contentment.  But  they  are  quite  as 
often  contradicted  as  confirmed  by  the  actual 
count.  A  warm  winter,  for  example,  may  be 
followed  by  a  cool  summer,  and  a  hot  summer 
by  a  cold  winter.  This  happens,  though,  no 
oftener  than  it  fails  to  happen.  Also  it  often 
happens  that  of  two  extreme  winters  or  of  two 
extreme  summers,  whether  hot  or  cold,  one 
conies  the  very  next  year  after  the  other.  All 
that  we  can  safely  expect  in  the  matter  is  that 
one  or  another  of  the  several  kinds  of  extreme 
season  will  occur  every  few  years,  and  that  there 
will  be  no  very  long  succession  of  what  to  us 
will  seem  quite  ordinary  seasons. 

It  is  always  grateful  to  us  to  think  that  the 
172 


HOT   AND   COLD   WAVES 

severity  of  one  season  will  be  made  up  to  us  by  a 
special  mildness  in  one  soon  to  follow.  And 
this  occurs  frequently  enough  quite  to  justify 
us  in  entertaining  it  at  least  as  a  hope,  if  not 
as  an  expectation.  There  is,  undoubtedly,  an 
equalization  of  the  extremes  of  weather.  But 
it  is  not  accomplished  too  promptly  or  too  open- 
ly. We  can  detect  it  only  in  proportion  as  we 
increase  the  number  of  years  through  which 
we  search  for  it.  Long  periods  offer  clearer 
proof  of  it  than  do  short  ones. 

An  extreme  season  is  not,  when  it  occurs, 
always  well  marked  in  all  parts  of  the  country. 
Sometimes  when  very  pronounced  in  one  part 
it  is  little  or  not  at  all  apparent  in  another. 
Usually,  whatever  its  kind,  its  general  strength 
is  greatest  through  the  central  region  between 
the  Rocky  Mountains  and  the  Appalachians. 
Its  highest  absolute  degree  may  not  be  attained 
there,  but  ordinarily  its  highest  average  will  be. 
It  may,  though,  show  also  within  this  region 
considerable  differences  between  different  parts, 
and  especially  between  North  and  South. 

Often  a  season  extreme  with  us  proves,  within 
our  latitude,  extreme  in  the  same  way  nearly 
or  quite  round  the  world.  This  fact  empha- 
sizes what,  indeed,  the  whole  character  of 


OUR   OWN    WEATHER 

extreme  seasons  indicates — that  they  are  not 
mere  casual  or  local  departures  from  ordinary 
weather.  They  must,  it  would  seem,  originate 
in  some  departure  of  the  atmosphere  itself 
from  its  usual  organization  and  movements. 
Perhaps  the  most  eager  pursuit  at  the  present 
time  of  the  many  faithful  students  and  observ- 
ers who  are  perfecting  the  science  of  the 
weather  is  to  find  out  just  what  of  this  kind 
does  occur  and  what  are  the  causes  of  it.  Al- 
most any  day  some  discovery  in  just  this 
direction  may  occur  that  will  be  of  incalculable 
value.  For  with  a  fuller  knowledge  of  the 
variations  of  the  atmosphere  at  large,  forecasts 
of  the  weather,  not  simply  for  a  few  days, 
but  for  the  seasons  and  the  year,  and  even  for 
a  series  of  years,  might  very  well  become 
possible.  To  expect  some  such  thing  is  not  in 
the  least  fantastic,  but  quite  within  probability. 

Unexplained  Variations  of  the  Atmosphere 

The  fact  that  there  are  such  variations  and 
something  of  their  character  are  already  known. 
For  instance,  the  movement  of  the  main  body 
of  the  atmosphere  in  our  latitude  never  ceases 
to  be  eastward,  but  it  is  known  to  change  its 
i74 


HOT    AND   COLD    WAVES 

speed.  One  time  it  is  very  rapid,  and  another 
time  very  slow.  This  associates  itself  inevi- 
tably with  another  thing  that  has  been  observed : 
that  the  whole  procession  of  cyclones  and  anti- 
cyclones, out  of  which  we  get  more  immediately 
our  ordinary  changes  of  weather,  has  some- 
times sudden  changes  in  its  speed  and  force, 
and  that  these  changes  may  appear  almost 
simultaneously  in  the  United  States,  Europe, 
and  Asia.  Then  it  is  known  that  at  any  one 
time  of  the  year  the  great  areas  of  air,  of  either 
high  or  low  pressure,  that  build  up  half  per- 
manently over  the  oceans  and  the  continents 
may  show  important  differences  in  their  loca- 
tion and  in  their  strength,  and  that  these  differ- 
ences have  much  to  do  with  the  weather. 

Our  own  summer  weather,  as  is  shown,  for 
example,  in  hot  waves  and  West  Indian  hurri- 
canes, has  dependence  of  the  clearest  kind  on 
the  particular  place  and  intensity  of  the  At- 
lantic area  of  high  pressure.  And  it  is  believed 
that  our  winter  weather  varies  more  or  less 
in  answer  to  the  lay  and  strength  of  the  great 
area  of  air  of  high  pressure  that  forms  in  win- 
ter over  northern  Asia. 

But  while  the  occurrence  and  something  of 
the  features  of  the  more  fundamental  atmos- 


OUR    OWN    WEATHER 

pheric  variations  are  already  known,  the  cause 
of  them  remains  still  very  much  hidden.  In  the 
eager  search  for  it  going  on  the  object  first  and 
most  questioned  is,  naturally,  the  sun.  The 
sun,  indeed,  is  just  now  as  if  it  were  a  trust 
under  investigation  by  a  congressional  com- 
mission— an  investigation  without,  though,  let 
us  hope,  any  politics  in  it.  The  sun  itself  shows, 
on  the  very  face  of  it,  that  it  changes  its  con- 
dition. It  offers  an  especially  conspicuous  mark 
of  this  in  the  sun  spots — those  areas  of  pro- 
found disturbance  that,  appearing  on  the 
surface  of  the  sun,  gradually  increase  in  num- 
ber and  in  size  through  a  period  of  something 
more  than  five  years,  then  through  an  equal 
period  gradually  diminish,  and  then  for  about 
the  sum  of  these  two  periods,  or  about  eleven 
years,  are  entirely  invisible,  at  least  to  human 
observation.  One  can  hardly  believe  that  a 
variation  so  constant  and  so  great  as  this 
apparently  is  does  not  have  some  effect  on  the 
weather,  seeing  that  the  energy  that  makes  the 
weather  comes  from  the  sun.  Hence,  the  pro- 
fessional effort  to  find  out  and  the  popular 
desire  to  know  are  both  eager. 

They  are  also  fairly  eager  in  another  inquiry : 
whether  of  the  energy  that  makes  the  weather 
176 


HOT   AND   COLD   WAVES 

all  really  does  come  from  the  sun,  and  whether 
at  least  some  small  fraction  of  it  may  not  be 
from,  say,  the  moon  or  the  planets  or  even  from 
the  stars.  We  can  none  of  us  give  up,  though  we 
may  yield  so  far  as  to  somewhat  veil,  our  in- 
herited belief  that  the  moon  has  much  to  do 
with  the  weather.  But  scientific  investigation 
finds  between  the  two  no  relation  or  connection 
that  is  appreciable.  It  also  finds  none  between 
the  weather  and  either  the  planets  or  the  stars. 
There  is  a  sense,  though,  with  regard  to  the 
moon  that  some  connection  may  yet  appear. 
There  is  also  this  sense,  but  less  strong,  with 
regard  to  the  planets,  and  even  —  though 
here  manifestly  feeble — with  regard  to  the 
stars. 

As  to  changes  of  weather  due  to  variations 
in  the  amount  of  energy  received  on  the  earth 
from  the  sun,  the  most  authoritative  opinion 
is  that,  while  recent  observation  and  study 
have  brought  out  much  that  is  suggestive  of 
such  changes,  there  is  as  yet  no  clear  proof  of 
their  occurrence.  But  the  most  conservative 
masters  of  the  subject  allow  that  it  may  have, 
at  almost  any  time,  a  sudden  and  quite  decisive 
unfoldment. 


177 


OUR   OWN    WEATHER 
Does  the  Nature  of  the  Seasons  Change? 

Almost  any  one  who  has  been  exposed  to  the 
weather  years  enough  to  begin  to  cherish 
memories  of  it,  is  likely  to  have  an  impression 
that  the  seasons  are  making  a  permanent 
change.  The  impression  is  due,  however,  more 
to  the  preciousness  of  the  memories  than  to 
their  perfection.  If  our  memories  of  the 
weather  were  more  comprehensive,  the  sense  of 
radical  change  in  it  would  be  less  common.  Of 
this  I  myself  once  had  a  peculiar  and  very 
interesting  proof. 

There  lived  in  a  town  where  I  was  conducting 
a  newspaper  a  woman  of  one  of  those  abnormal 
memories  that  carry,  without  once  dropping, 
anything  and  all  that  is  handed  them.  She  was 
eighty  years  old,  had  lived  all  her  life  in  that 
town,  and,  having  no  special  employment  for 
her  memory,  had  laid  up  in  it  whatever  chanced 
to  catch  her  attention.  She  remembered 
dates  of  birth,  of  marriage,  and  of  death,  and 
incidents  of  the  ordinary  life  of  the  town  in 
marvelous  profusion.  She  was  an  authority  to 
people  who  had  had  part  in  them  on  occur- 
rences in  which  she  herself  had  had  none.  But 
it  was  in  the  matter  of  the  weather  that  her 
178 


HOT    AND    COLD    WAVES 

opulence  and  exactness  of  memory  most  shone. 
This  suggested  that  a  review  by  her  of  the 
weather  as  she  herself  had  experienced  it  would 
make  a  good  article  for  the  newspaper. 

The  article  was  prepared,  and  proved  to  be, 
what  articles  as  a  rule  seem  so  bound  not  to  be, 
better  even  than  the  editor  had  anticipated. 
It  was,  indeed,  wonderful.  It  recalled,  wholly 
from  memory,  the  weather  of  fifty  years,  not 
only  year  by  year,  but  season  by  season,  and 
even  in  many  of  its  sallies  on  particular  days 
with,  in  most  instances,  the  exact  date  of  the 
day.  It  was  interesting  primarily,  of  course, 
as  a  feat  of  memory ;  but  it  was  scarcely  less  so 
as  a  story.  To  me,  who  was  already  acquiring 
from  my  own  loose  recollections  the  common 
belief  that  the  seasons  were  no  longer  what  they 
had  been,  the  most  impressive  thing  finally  in 
the  review  was  its  clear  indication  that  the 
seasons,  in  spite  of  their  freaks  and  excesses, 
remained  entirely  true  to  themselves,  that 
fundamentally  they  disclosed  no  change. 

And  this,  in  effect,  is  the  conclusion  also  of 
all  scientific  inquiries  into  the  matter.  Such 
inquiries  have  been  made  from  time  to  time 
with  the  utmost  care,  and  the  conclusion, 
drawn  from  comparison  and  analysis  of  author- 
179 


OUR   OWN    WEATHER 

itative  weather  records  for  the  full  periods 
through  which  such  records  have  been  kept,  is 
that  the  seasons  maintain  an  average  practically 
invariable  of  strength,  deportment,  and  effect. 
But  notwithstanding  this  nobody  can  believe, 
in  view  of  the  known  mutability  of  the  entire 
universe,  that  fundamentally  the  seasons  do 
not  change.  They  must  change;  they  cannot 
possibly  save  themselves  from  change.  But 
the  change,  apparently,  is  of  that  grand,  slow 
order  which  the  universe  is  fond  of,  and  which, 
being  hidden  from  ordinary  perception,  is  for 
ordinary  human  life  and  endeavor  practically 
non-existent. 


XI 

THE     WINDS 

A,L  over  the  country  the  natural  tendency 
of  the  wind  is  to  blow  from  west  to  east. 
It  is  a  tendency  much  interfered  with  by  the 
irregularities  of  the  land,  and  yet  more  by  the 
frequent  breaking  of  the  air,  under  differences 
of  temperature,  into  those  persistent  whirls 
which  we  know  as  cyclones  and  anticyclones. 
But  in  spite  of  all  hindrances  much  the  largest 
part  of  the  wind  in  the  course  of  the  year  is  from 
the  west. 

The  point  in  the  west  from  which  it  comes 
most  is  the  northwest.  This,  however,  is  more 
its  habit  in  the  winter  half  of  the  year  than  in 
the  summer  half.  The  lessening  pressure  of  air 
down  from  the  north,  under  the  tempering  ad- 
vance of  spring  and  summer,  and  the  increasing 
pressure  of  air  into  the  country,  especially  into 
the  southern  half,  from  the  relatively  cool 
oceans  and  Gulf  produce  in  summer  some- 
181 


OUR   OWN    WEATHER 

what  of  a  shift  of  the  entire  wind  system.  Under 
this,  winds  from  points  in  the  west  diminish 
and  winds  from  points  in  the  east  increase, 
particularly  southeast  winds.  Those  from  the 
west  still  remain,  on  the  whole,  the  prevailing 
ones;  but  they  show  the  strengthened  pressure 
of  the  air  from  the  south  in  that  now  more  of 
them  are  from  the  southwest  and  fewer  from  the 
northwest  than  in  winter. 

This  gives  the  southwest  winds  an  approach 
in  quantity  to  the  northwest  winds,  but  only 
an  approach.  The  northwest  remain  for  the 
year  considerably  the  larger  part  of  all  the 
winds  from  western  points.  Winds  directly 
from  the  west  are  much  fewer  than  those  from 
either  the  northwest  or  the  southwest.  They 
are  much  more  frequent,  however,  than  winds 
directly  from  the  east,  which  are  the  fewest  of 
all  recorded. 

The  Winds  in  the  Different  Parts  of  the 
Country 

Naturally,  in  its  disposition  to  blow  from 

west  to  east  whenever  it  can  the  wind  meets 

with  more  obstruction  in  some  parts  of  the 

country  than  in  others.    The  conditions  espe- 

182 


»    2, 

Q     «l 

S  ~; 

pi 


»-iu 

o    Sga 


w    o  ^ 
o    l|' 

aS     <"•>- 


S     §"°  « 

2  Mi 


THE    WINDS 

daily  favor  it  just  along  the  Pacific  coast.  The 
eastward  movement  of  the  general  atmosphere, 
constant  throughout  the  year,  combines  in 
summer  with  a  draft  created  by  the  superior 
heat  of  the  land,  and  the  air  comes  in  largely 
from  the  ocean.  It  suffers  little  disturbance 
until  it  reaches  the  mountains. 

From  a  half  to  three-quarters  of  the  entire 
wind  of  the  year  on  the  Pacific  coast  is  from 
some  part  of  the  west.  The  proportion  is  less 
on  the  north  coast  than  on  the  south,  and  is 
most  on  the  middle  coast,  in  the  region  of  San 
Francisco.  It  is  there  from  seventy  to  seventy- 
five  per  cent.,  which  is  considerably  larger  than 
the  proportion  shown  in  any  other  part  of  the 
country.  Along  most  of  the  coast  it  is  the 
northwest  winds  that  prevail;  but  at  San  Fran- 
cisco and  again  at  Los  Angeles  it  is  the  west 
wind.  No  other  points  in  the  country  show  as 
large  a  proportion  of  direct  west  wind  as  these. 
There  are  months  during  which  the  prevailing 
winds  at  certain  points  are  from  either  the 
north  or  the  south,  or  else  from  northeast  or 
southeast.  But  even  at  such  points  the  west 
and  westerly  winds  remain  the  prevailing  ones 
for  the  year. 

In  the  plateau  and  mountain  regions,  from 
183 


OUR   OWN   WEATHER 

the  northern  border  of  Idaho  and  Montana  to 
the  southern  border  of  Arizona  and  New  Mexico, 
winds  from  some  part  of  the  west  are  still  in 
much  the  larger  proportion.  But  there  is 
about  an  even  division  between  those  from  the 
northwest  and  those  from  the  southwest,  some 
districts  having  the  one  and  some  the  other  as 
the  prevailing  wind  of  the  year.  Two  districts 
here  show  what  is  not  shown  anywhere  along 
the  Pacific  coast — prevailing  winds  for  the  year 
from  some  part  of  the  east.  They  are  the  dis- 
tricts of  Salt  Lake  and  Santa  Fe,  in  both  of 
which  the  prevailing  winds  are  southeast.  In 
most  of  the  districts  here  there  is  but  slight 
change  from  month  to  month,  and  in  several 
what  is  the  prevailing  wind  for  the  year  is  also 
the  prevailing  one  for  every  month  in  the  year. 
This  is  the  case  at  Denver,  Colorado,  where  the 
prevailing  wind  is  from  the  south;  and  also  at 
Helena,  Montana,  where  it  is  from  the  south- 
west. 

From  the  Rocky  Mountains  eastward, 
through  nearly  all  the  central  regions  to  the 
Appalachians,  winds  from  some  part  of  the 
west  still  remain  the  prevailing  ones  of  the 
year.  But  they  are  less  markedly  so  here  than 
in  any  other  of  the  large  divisions  of  the  country ; 
184 


THE   WINDS 

and  there  is  here  a  more  pronounced  varia- 
tion between  winter  and  summer  of  wind  direc- 
tions than  in  any  other  division.  Through 
the  Dakotas,  Minnesota,  Wisconsin,  Michigan, 
northern  Illinois,  Iowa,  Nebraska,  Kansas,  and 
Missouri  the  largest  proportion  of  the  wind 
movement  of  the  year  is  from  the  northwest. 
But  under  the  falling  away  of  northwest  winds 
in  summer  southwest  winds  become  in  various 
parts  the  prevailing  ones  of  summer,  and  enough 
so  in  some  to  show  as  the  prevailing  ones  for  the 
entire  year.  The  spring  and  summer  shift  in- 
troduces also  southeast  winds;  and  these  too, 
by  virtue  of  this  admission,  are  able  to  show  in 
a  few  districts  as  the  prevailing  ones  of  the  year. 

Through  southern  Illinois,  Indiana,  Ohio, 
Kentucky,  and  Tennessee  there  is  more  of  south- 
west wind  than  of  northwest;  but  between 
them  they  give  the  general  movement  from  west 
to  east  a  clear  predominance  for  the  year.  This 
is,  though,  so  far  modified  in  summer  that 
south  wind  in  some  districts  and  southeast  wind 
in  others  become  prevailing  for  certain  months, 
and  in  a  few  instances  for  the  whole  year. 

Thus  through  both  the  north  and  the  middle 
of  the  central  regions  the  westerly  winds  keep 
their  ascendancy  for  the  year,  though  much 
185 


OUR   OWN    WEATHER 

displaced  in  summer  by  the  southerly  and  east- 
erly. But  in  the  part  comprising  Arkansas, 
Mississippi,  Louisiana,  and  Texas  they  quite 
lose  it.  Here  the  prevailing  wind  for  the  year, 
while  different  in  different  districts,  is  almost 
invariably  from  either  the  south  or  the  south- 
east. Northwest  winds  prevail  through  the 
winter  at  some  points ;  but  in  most  districts  they 
attain  to  prevalence  for  not  a  single  month  in 
the  year. 

Such  losses  as  the  winds  from  western  points 
suffer  in  the  central  regions  they  quite  recover 
in  the  regions  of  the  Atlantic  coast.  Through 
New  England,  the  state  of  New  York,  Pennsyl- 
vania, New  Jersey,  Delaware,  Maryland,  and 
Virginia  the  prevailing  wind  for  the  year  is, 
speaking  generally,  everywhere  the  northwest 
wind.  It  gives  place  through  the  summer  to  the 
southwest  wind,  and  that  is  the  prevailing  one 
for  each  of  the  three  summer  months.  Such 
departures  from  this  distribution  as  occur  are 
confined  to  individual  districts  and  make  but 
a  small  exception  to  the  rule. 

The  southwest  winds  supersede  the  north- 
west through  North  and  South  Carolina,  and 
become  the  prevailing  ones  for  the  year.  But 
they  yield  the  prevalence  to  northeast  winds 
1 86 


THE   WINDS 

through  the  autumn  months  and  December. 
This  distribution  appears  also  in  Florida;  with, 
though,  an  extension  of  the  term  of  the  north- 
east winds,  so  that  these  are  the  prevailing  ones 
for  the  year  and  the  southwest  predominate 
only  in  summer.  The  eminence  thus  shown  in 
the  northeast  winds  is  peculiar  to  that  region; 
it  appears  nowhere  else  in  the  country.  It 
extends  somewhat  into  Georgia,  but  in  northern 
Georgia  the  northwest  winds  are  again  in  almost 
exclusive  prevalence ;  and  the  sum  of  the  matter 
for  the  south  Atlantic  states,  as  for  the  middle 
and  the  north  Atlantic,  is  a  strong  predomi- 
nance for  the  year  of  winds  from  some  part  of 
the  west. 

Sea-breezes  and  Cyclonic  Winds 

And  this  is  just  the  opposite  of  what  one  might 
have  guessed,  in  view  of  the  great  account 
taken  along  the  Atlantic  coast,  in  speech  and 
in  feeling,  of  two  features  of  the  wind  move- 
ment there :  the  easterly  gale  and  the  sea-breeze, 
which,  of  course,  is  also  easterly.  It  is  the 
harshness  of  the  one  and  the  graciousness  of  the 
other,  more  than  the  actual  frequency  of  either, 
that  makes  them  impressive. 

The  strict  sea-breeze  is  but  a  slender,  short- 
13  187 


OUR   OWN    WEATHER 

lived  affair.  It  arises  only  in  summer,  with 
some  laps  into  the  later  spring  and  the  earlier 
autumn,  and  lasts  each  day  only  from  the 
middle  of  the  forenoon  until  toward  evening — 
that  is,  during  the  hours  when,  under  the  daily 
mount  of  the  sun,  the  surface  of  the  land  is 
efficiently  hotter  than  that  of  a  narrow  strip  of 
the  water  bordering.  It  begins  at  a  somewhat 
less  distance  out  than  it  extends  inland,  and  its 
extension  inland  is,  on  an  average,  not  more 
than  twenty-five  or  thirty  miles.  To  the  general 
Atlantic  coast  region  more  tempering,  probably, 
than  the  sea-breeze  are  the  bodies  of  air  so  fre- 
quently drawn  in  from  the  sea  under  the  ad- 
vance of  cyclones.  It  is  just  bodies  of  air  so 
drawn  in  that,  making  their  approach  with 
extreme  eagerness,  raise  the  easterly  gale;  and 
their  easterly  movement  is  apt  to  be  more 
or  less  offset  in  each  instance  by  the  westerly 
winds  that  always  attend  the  cyclone's  depar- 
ture. 

Nothing  in  all  the  wind  distribution  is  of 
greater  interest  than  that  in  the  central  regions, 
while  the  west  and  westerly  winds  maintain  a 
clear  predominance,  they  are  more  nearly 
equaled  there  by  winds  from  other  quarters 
than  in  any  other  part  of  the  country.  It  is  in 
188 


THE    WINDS 

the  central  regions  that  the  appearance  of  cy- 
clones and  anticyclones  is  most  constant  and 
that  they  are  least  disturbed  or  perverted  in 
their  movements  and  effects.  The  abundance 
there  of  easterly  and  south  winds,  in  comparison 
with  westerly,  is  a  striking  mark,  therefore,  of 
how  truly  organizations  these  areas  of  air  are, 
and  also  how  effective  in  the  nature  and  office 
imputed  to  them — that  of  creating,  the  one  to- 
ward them,  the  other  from  them,  movements  of 
air  on  all  sides.  The  fact  that  the  westerly 
winds  still  remain  the  more  frequent  only 
adds  sharpness  to  the  exhibition,  since  it  shows 
that  in  the  lulls  which  we  know  to  occur  in 
the  general  cyclone  and  anticyclone  movement 
the  air  simply  settles  down  into  its  normal 
direction  of  from  west  to  east.  And  consider- 
ing over  what  a  great  width  of  country  this  all 
so  clearly  appears,  we  get  from  it  a  better  sense 
than,  perhaps,  from  anything  else  of  the  magni- 
tude and  at  the  same  time  of  the  precision  of 
our  system  of  weather. 

The  Velocity  of  the  Wind 

The  general  wind  velocity  has  on  land — but 
not  on  the  open  sea — a  daily  increase  and  de- 
189 


OUR   OWN    WEATHER 

cline  like  that  shown  in  sea-breezes.  It  begins 
to  quicken  early  in  the  morning  as  soon  as  the 
lower  layers  of  air  begin  to  feel  the  heat  of  the 
sun.  It  continues  to  quicken  until  two  or  three 
o'clock  in  the  afternoon,  and  then  begins  to 
decline.  The  time  of  greatest  stillness  is  in  the 
after  part  of  the  night.  This  daily  variation  is, 
however,  lost  in  the  midst  of  a  storm. 

The  general  strength  of  the  winds  is  much 
greater  through  the  winter  half  of  the  year 
than  through  the  summer  half;  but  the  months 
in  which  it  is  greatest  are  spring  months — 
first  March  and  then  April.  The  two  months 
in  which  it  is  least  are  July  and  August.  Of 
positive  calm  there  is  in  most  places  scarcely 
enough  in  the  course  of  the  year  to  make  a 
record.  At  such  places  as  it  does  make  a  rec- 
ord it  is  about  as  much  a  winter  product  as 
a  summer. 

The  winds  became  classified  long  ago  accord- 
ing to  their  strength,  under  simply  the  prompt- 
ing of  human  feeling.  The  weather  authorities 
have  adopted  this  classification,  merely  adding 
the  measures  needful  for  their  nicer  uses.  A 
light  wind,  for  instance,  is  what  we  have  always 
known  it  to  be.  But  according  to  one  well- 
approved  scale  it  must  be  of  a  velocity  not  ex- 
190 


THE    WINDS 

ceeding  three  miles  an  hour.  A  velocity  of 
anything  more  than  that  up  to  and  including 
five  miles  an  hour  makes  a  gentle  wind;  and 
this,  according  to  a  useful  instruction  issued 
for  the  general  guidance,  "moves  leaves  of 
trees."  The  other  kinds  and  their  velocities 
and  traits  are:  Fresh — 6  to  14  miles  an  hour: 
"moves  small  branches  of  trees."  Brisk — 15 
to  24  miles  an  hour:  "good  sailing  breeze  and 
makes  whitecaps."  High — 25  to  39  miles  an 
hour:  "sways  trees  and  breaks  small  branches." 
Gale — 40  to  59  miles  an  hour:  "dangerous  for 
sailing-vessels."  Storm  —  60  to  79  miles  an 
hour:  "prostrates  exposed  trees  and  frail 
houses."  And,  last  but  not  least,  hurricane — 
80  or  more  miles  an  hour:  "prostrates  every- 
thing." The  final  characterization  seems  a 
little  strong,  in  view  of  the  fact  that  sky- 
scrapers in  New  York  withstand  winds  of  more 
than  a  hundred  miles  an  hour.  But  it  was  in- 
tended, no  doubt,  especially  for  a  warning  at 
sea,  where,  of  course,  the  situation  is  always 
delicate. 

The  parts  of  the  country  in  which  the  winds 

show  greatest  strength  are,  first,  the  two  coasts, 

the  Atlantic  and  the  Pacific,  on  the  one  from 

South  Carolina  northward  and  on  the  other 

191 


OUR   OWN    WEATHER 

from  San  Francisco  northward;  and,  then, 
along  the  shores  of  the  Great  Lakes  and  in 
front  of  the  Rocky  Mountains,  over  the  Great 
Plains.  Around  the  Lakes  they  are  much 
stronger  on  the  south  shores  than  on  the  north ; 
and,  clearly,  what  gives  them  their  special  in- 
tensity is  the  comparative  smoothness  of  the 
surface  over  which  they  travel.  And  it  is  main- 
ly owing  to  a  surface  more  nearly  like  that  of  a 
great  body  of  water  than  is  shown  in  any  other 
great  stretch  of  land  in  the  country  that  the 
winds  are  peculiarly  strong  over  the  Plains. 

But  along  the  coasts,  in  addition  to  any 
special  strength  they  may  get  through  coming 
largely  from  off  the  water,  they  are  apt  to  get 
both  a  greater  velocity  and  a  greater  violence 
from  the  sharp  differences  of  temperature  often 
arising  there  between  land  and  water  and  the 
sharp  obstructions  presented  by  the  land. 
They  especially  rage  about  abrupt  projections 
of  land,  like  Point  Reyes,  on  the  Pacific  coast, 
and  Cape  Hatteras,  on  the  Atlantic. 

The  prevalence  of  high  winds  depends,  in 
most  parts  of  the  country,  mainly  on  the  fre- 
quency and  strength  of  cyclones.  The  contour 
of  the  land  and  even  its  growths — its  wooded- 
ness  or  treelessness  —  make  great  differences 
192 


THE    WINDS 

for  different  places.  But,  leaving  these  out  of 
the  account,  the  liability  of  particular  points 
or  districts  to  such  winds  corresponds  rather 
closely  to  their  situation  with  reference  to  the 
ordinary  cyclone  tracks.  Some  of  the  more 
aptly  situated  have  achieved  even  in  the  winds 
of  the  rarity  of  gales — winds  of  forty  miles  or 
more  an  hour — an  imposing  record.  At  Ama- 
rillo,  Texas,  during  a  period  of  ten  years  there 
were  gales  on  756  days — an  average  of  seventy- 
five  days  in  the  year.  The  record  at  Huron, 
South  Dakota,  during  the  same  period,  while 
much  below  this,  was  still  not  mean — 357  days 
with  gales.  At  both  places  the  month  that 
had  the  largest  number  was  April. 

Special  Winds — The  Chinook 

In  some  instances  local  peculiarities  of  the 
wind  have  prevailed  through  a  wide  enough 
region  and  with  enough  distinction  to  give  the 
winds  in  which  they  appear  a  special  name. 
In  eastern  Montana  and  southward  into  north- 
ern Texas  very  frequent,  and  in  winter  often 
very  injurious,  are  what  are  known  as  "north- 
ers." They  are  simply  the  winds  that  always 
blow  into  the  rear  of  a  cyclone,  but  showing  here 
i93 


OUR   OWN    WEATHER 

more  severity  and  more  of  northerly  and  less 
of  westerly  direction  than  in  other  regions.  It 
is  winds  of  the  same  class,  but  extraordinarily 
strong  and  laden  with  fine,  prickly  snow,  that 
constitute  the  blizzard,  which  attains  its  great- 
est severity  in  North  Dakota. 

The  most  curious  and  truly  original  of  the 
special  winds  is  the  "chinook."  We  expect  air 
brought  down  from  the  tops  of  high  mountains 
to  be  cool.  And  we  expect  this  also  of  air 
moving  in  pursuit  of  a  cyclone.  The  chinook 
is  a  wind  that  works  the  miracle  of  carrying 
air  down  from  the  mountain-tops  and  into  the 
rear  of  a  cyclone,  and  at  the  same  time  spread- 
ing a  great  warmth  through  the  region  it  tra- 
verses. The  eastern  slope  of  the  Rocky  Moun- 
tains in  Montana,  Wyoming,  and  Colorado  is 
the  main  field  of  its  activity.  Its  method, 
once  a  good  deal  of  a  mystery,  but  now  quite 
well  understood,  is  simple  enough. 

The  chinook  is  nothing  more  than  an  ex- 
traordinarily swift  and  sheer  tumbling  down  of 
a  body  of  air  from  the  mountain  heights  into 
openings  offered  by  a  body  that  is  flowing  off 
from  the  lower  slopes  under  the  draft  of  a 
cyclone  at  some  little  distance  to  the  eastward. 
The  lower  body  is  cold.  The  upper  body  is,  at 
194 


THE   WINDS 

its  start,  cold  also.  But,  like  all  bodies  of  de- 
scending air,  it  warms  under  the  force  of  de- 
scent, and  as  this  force,  under  the  conditions 
then  prevailing,  is  particularly  strong,  the  air, 
by  the  time  it  reaches  the  lower  ground,  is 
much  warmer  than  that  of  which  it  takes  the 
place.  Moreover,  it  was  to  begin  with  extreme- 
ly dry,  and  the  warmth  it  acquires  in  its  rapid 
fall  makes  it  greedy  of  moisture.  It  drinks  up 
all  that  comes  in  its  way,  and  so  becomes  doubly 
transforming — both  warming  and  drying — to 
the  temperature  of  the  regions  over  which  it 
spreads. 

The  changes  the  chinook  effects  are  some- 
times of  a  suddenness  and  degree  that  one  can 
hardly  credit.  It  can  occur  only  when  at  the 
places  to  which  it  descends  the  weather  is  cold. 
A  temperature  of  anywhere  from  zero  to 
thirty  degrees  below  will  be  prevailing.  Sud- 
denly a  wind  starts  up  from  the  southwest,  and 
in  fifteen  minutes  the  temperature  will  have 
leaped  to  anywhere  from  ten  to  forty  degrees 
above  zero.  Rises  of  temperature  of  even 
more  than  forty  degrees  under  the  Chinook's 
visitations  occur;  but  a  rise  of  forty  is  about 
the  most  that  is  ever  effected  by  the  first 
onset. 


OUR    OWN    WEATHER 
The  Higher  We  Go,  the  Stronger  the  Wind 

As  we  are  made  aware  almost  any  time  when 
we  ascend  to  the  housetop  or  to  an  open  hill- 
top, the  velocity  of  the  wind  increases  with 
elevation.  The  increase  is  at  a  more  rapid 
rate  down  low  than  high  up.  This  it  naturally 
would  be;  for  in  its  lower  section  the  ascent 
is  an  almost  instant  stripping  away  of  bulky 
obstructions,  such  as  buildings  and  sharp  out- 
croppings  of  land.  Anywhere  well  above  all 
such  obstructions  the  change  of  conditions 
with  ascent  becomes  relatively  slight.  But 
the  increase,  while  more  rapid,  is  also,  as  any 
one  can  see  that  it  must  be,  much  less  regular 
below  than  above.  This  causes  some  embarrass- 
ment to  the  weather  observers.  Their  observa- 
tions of  wind  direction  and  velocity,  to  have 
any  general  value,  must  be  made  at  somewhat 
of  an  elevation,  and  they  always  are.  But 
there  is  no  real  telling  what  elevation  at  one 
and  another  station  will  put  the  several  stations 
on  an  equality  with  reference  to  the  irregu- 
larities down  on  the  ground.  The  observers 
meet  the  difficulty  as  best  they  can  by  their 
skill  in  calculation ;  and  this  is  quite  well  enough 
for  most  practical  purposes. 
196 


THE    WINDS 

They  would  have  another  embarrassment  in 
the  fact  that  the  winds  never  come  in  a  continu- 
ous flow,  but  always  in  rises  and  falls,  only  that 
they  have  subdued  the  wind  into  making,  with 
the  aid  of  automatic  devices,  its  own  record. 
All  through  the  day,  all  through  the  night,  and 
all  through  the  year,  and  whether  any  observer 
is  present  or  not,  it  is  tracing  on  paper,  in  a 
plain,  infallible  line,  just  as  if  it  were  a  human 
draftsman,  its  every  descent  and  mount  in 
strength,  from  none  at  all  to  the  mightiest  it  is 
capable  of.  Because  of  this  ingenious  manage- 
ment of  it  a  thing  always  invisible  and  ever 
varying  gets  exhibited  to  us,  at  chosen  places 
of  observation,  in  its  quality  and  action  with 
such  a  constancy  and  minuteness  as  was  never 
any  human  being  nor,  indeed,  any  living  crea- 
ture. 


XII 

CLOUDS    AND    SUNSHINE 

IN  periods  of  dark  weather  it  might  comfort 
us  to  remember  that,  on  the  whole,  we  have 
sunshine  more  than  half  the  time — that  is,  of  the 
time  when  the  sun  is  present,  of  the  daytime. 
Seeing  how  necessary,  after  all,  clouds  and  their 
frequent  consequence,  rain,  are  to  us,  this 
seems  a  generous  amount.  But,  of  course,  all 
parts  of  the  country  do  not  share  alike  in  it. 
Always,  the  warmer  the  air  the  more  moisture 
it  can  carry  without  forming  clouds;  and  the 
average  fairness  of  a  region  is,  therefore,  always 
according  to  the  proportion  prevailing  there  be- 
tween the  moisture  of  the  air  and  its  warmth. 

This  proportion  has  many  variations  under 
the  successions  of  day  and  night,  the  rotation 
of  the  seasons,  and  the  passage  of  storms.  But 
it  is  easily  reduced  to  an  average,  and  to  that 
the  average  of  sunshine  is  bound  to  correspond. 
Places  where  the  ordinary  moisture  is  abundant 
198 


CLOUDS  AND   SUNSHINE 

and  the  ordinary  temperature  relatively  low 
are  the  cloudy  places.  Those  where,  on  the 
other  hand,  the  moisture  is  scant  and  the 
temperature  relatively  high  are  the  fair  ones. 

The  north  Atlantic  and  the  north  Pacific 
coasts  and  the  lower  shores  of  the  Great  Lakes 
offer  just  the  right  conditions  for  cloudiness. 
Their  latitude  gives  them  a  low  average  tem- 
perature, and  the  neighboring  bodies  of  water 
give  them  much  moisture.  These  are,  there- 
fore, just  the  parts  of  the  country  that,  on  the 
whole,  have  the  least  amount  of  sunshine.  In 
the  north  Pacific  states,  taking  winter  and 
summer  together,  there  is  sunshine  for  not  more 
than  four-tenths  of  the  time  (that  is,  of  the 
daytime);  and  for  winter  only  the  average 
falls  to  about  three-tenths.  The  amount  is  not 
so  small  as  this  along  the  Lakes  or  in  any  of 
the  north  Atlantic  states.  The  annual  pro- 
portions there  for  the  places  that  have  least 
are  from  four-tenths  to  five-tenths. 

The  part  of  the  country  that  has  most  sun- 
shine is  that  southwest  region  which,  shut  off 
from  the  Pacific  Ocean,  the  only  near  body  of 
water,  by  high  mountains,  and  lying  in  a  warm 
latitude  and  also  out  of  the  path  of  general 
storms,  holds  the  record  against  all  other  parts 
199 


OUR   OWN    WEATHER 

of  the  country,  and  even  against  a  good  part 
of  the  world,  for  dryness  and  heat.  It  com- 
prises portions  of  California,  Nevada,  Arizo- 
na, and  New  Mexico.  It  has  sunshine  seven 
or  eight  tenths  of  all  the  daytime  of  the 
year. 

Outside  of  these  few  and  comparatively 
small  regions  where  the  amount  of  sunshine 
is  either  most  or  least,  the  distribution  of  it 
is  strikingly  even.  In  practically  all  the  rest 
of  the  country  there  is  sunshine  for  always 
something  more  than  five-tenths,  but  for  never 
much  more  than  six-tenths,  of  the  daytime 
part  of  the  year.  There  is  rather  more  in  the 
southern  half  of  the  country  than  in  the  north- 
ern. The  air  is  ordinarily  moister  through 
most  of  the  southern  half  than  through  most  of 
the  northern.  But  it  is  also  ordinarily  warmer, 
and  so  much  warmer  that  it  is  less  often  forced 
to  gather  its  burden  of  moisture  up  into  clouds. 
And  exactly  this  condition  marks  the  summer 
in  contrast  with  the  winter;  and  there  is  every- 
where considerably  more  sunshine  in  summer 
than  in  winter.  The  ordinary  difference  shows 
places  that  have  sunshine,  say,  six-tenths  of  the 
time  in  July  as  having  it  only  about  five-tenths 
of  the  time  in  January.  But  there  are  places 


CLOUDS  AND   SUNSHINE 

where  the  difference  between  summer  and  win- 
ter is  three  and  even  four  times  this. 

The  Ordinary  Midday  Cloud 

While  our  allowance  of  sunshine  is,  on  the 
whole,  generous,  there  are,  except  in  the  dryest 
parts  of  the  country,  comparatively  few  days 
that  show  no  clouds.  Over  the  larger  part  of 
the  country  the  appearance  of  a  certain  kind 
of  cloud  is  a  mark,  indeed,  of  the  day's  fairness. 
The  sun  rises  clear ;  the  ground  and  the  air  near- 
est it  begin  to  warm.  Then  the  air,  as  it  warms, 
begins  to  rise,  and  about  the  middle  of  the 
morning  there  begin  to  appear,  not  very  high 
up  in  the  sky,  bodies  of  cloud  that  look  like 
heaps  of  snow  floating  on  a  smooth  and  brill- 
iant sea.  Such  clouds  have,  as  a  rule,  a  well- 
marked,  straight  base;  and  it  is  this,  added  to 
a  slow,  steady  movement  on  just  one  plane, 
that  especially  gives  them  the  aspect  of  floating 
on  a  surface  of  smooth  water. 

All  that  is  necessary  to  the  formation  of  such 
clouds  is  that  the  lower  air  shall  be  fairly  moist 
and  that  just  the  ordinary  daily  warming-up 
shall  be  enough  to  cause  it  to  rise  to  a  height 
where,  cooled,  mainly  by  its  own  expansion 


OUR    OWN    WEATHER 

against  the  colder  air  about  it,  it  shall  be  forced 
to  condense  some  of  the  moisture.  Condensa- 
tion begins  at  the  uneven,  upper  fringes  of  the 
ascending  stream;  and  the  resulting  cloud 
shows,  therefore,  either  a  quite  irregular  or  else 
a  definitely  rounded  top.  As  by  continuing 
ascent  more  of  the  stream  comes  into  the  region 
of  condensation  the  cloud  builds  up  higher. 
But  the  base  of  the  cloud  remains  on  the  line 
where  condensation  becomes  possible.  This, 
obviously,  it  must  do.  It  could  not  wait  until 
it  got  above  that  line  to  form ;  and  if  it  fell  below, 
it  would  be  blotted  out.  The  line  need  not 
always  be  straight.  But  it  tends  to  be  so  in  the 
placid,  even  weather  to  which  clouds  of  the 
kind  in  question  are  peculiar.  Also,  it  is  high- 
er or  lower  according  to  the  amount  of  moisture 
in  the  ascending  column.  With  a  small  amount 
the  column  will  be  able  to  rise  to  a  colder — 
which  means,  to  a  higher — level  without  con- 
densation than  with  a  large  amount. 

Because  of  its  heaped-up  form  this  kind  of 
cloud  is  known  as  cumulus.  Appearing  as  it 
does  in  the  middle  of  the  day  and  in  an  open, 
clear  sky,  it  is  seen  more  nearly  in  its  complete 
form  than  any  other  kind,  and  is  of  all  the  easiest 
to  identify.  When  one  has  formed,  it  drifts 


CLOUDS    AND   SUNSHINE 

away  under  the  general  movement  of  the  layer 
of  air  in  which  it  has  formed.  Then,  perhaps, 
at  the  same  place  another  and,  following  that, 
another  will  form.  Or  perhaps  others  have 
formed  at  places  a  little  removed,  but  on  the 
same  level.  There  will  then  be  seen  a  line  of 
clouds  moving  peacefully  along,  like  a  line  of 
high-laden  barges. 

The  movement  is  very  slow — as  a  rule,  less 
than  a  mile  an  hour.  But  the  voyage  is  rarely 
long.  The  level  on  which  it  proceeds  is  usually 
not  more  than  a  mile  above  the  ground,  and 
easily  feels  any  change  of  condition  offered 
there,  and  soon,  by  its  own  inequalities  or  per- 
turbations, makes  shipwreck  of  the  fragile  craft 
it  is  floating.  But  the  number  of  clouds  swim- 
ming about  a  little  and  then  dissolving  increases 
until  after  the  middle  of  the  day.  Then  they 
cease  to  form ;  one  by  one  those  already  formed 
vanish,  and  by  nightfall  the  sky  is  clear  of 
them. 

While  this  kind  of  cloud-making  is  common 
over  a  large  part  of  the  country,  it  is  always,  in 
the  actual  proceeding,  a  very  local  as  well  as 
transient  affair.  The  amount  of  it  is  dependent 
mainly  on  the  conditions  at  a  given  time  and 
place.  There  is  more  of  it,  though,  everywhere 
14  203 


OUR   OWN   WEATHER 

in  summer  than  in  winter,  because  the  lower 
air  has  then  more  moisture  and  warms  up 
more  under  the  daily  passage  of  the  sun. 

Fog 

This  is  cloud  formation  in  its  most  familiar 
and  simplest  exhibition.  It  is  the  cooling  and 
condensation  of  a  column  or  body  of  air  at  the 
top.  But  we  have  an  even  more  familiar  ex- 
ample of  precisely  the  same  transformation  in 
the  cooling  and  condensation  of  a  body  of  air 
at  the  bottom.  Relatively  warm,  moist  air  in 
contact  with  the  ground  at  a  time  when  the  latter 
is  cooling  rapidly  suffers  the  same  effect  as  if  it 
had  risen  into  a  layer  of  cooler  air.  The  product, 
in  this  case,  is  not  known  as  cloud,  but  as  fog. 
There  is  no  essential  difference  between  the  two, 
however;  and  when  a  bank  of  fog  either  is 
carried  up  or  forms  a  little  above  the  ground, 
as  often  happens,  it  becomes,  by  virtue  merely 
of  position,  cloud  of  the  kind  known  as  stratus — 
a  horizontal  sheet  or  layer.  Building,  as  it 
does,  against  the  unyielding  surface  of  the 
ground,  it  more  inevitably  becomes  a  sheet  or  a 
succession  of  close  layers  than  a  cloud  formed 
at  the  top  of  a  column  of  air  pushing  up  through 
other  air  unevenly. 

204 


-^fe- 
lt!! 

til! 
11*1 1 


CLOUDS   AND   SUNSHINE 

It  is  largely  under  the  advance  of  the  sun 
that  clouds  are  formed.  For  the  whole  year 
and  the  whole  country  midnight  is  the  part 
of  the  day  when  there  is  least  cloudiness,  and 
from  two  to  three  o'clock  of  the  afternoon  is 
that  in  which  there  is  most.  But  fog  is  at- 
tendant largely  upon  the  decline  of  the  sun. 
It  forms,  not  exclusively,  but  oftenest,  at  even- 
ing or  night,  as  the  earth  loses  the  heat  acquired 
during  the  day ;  and  its  tendency  is  to  dissipate 
as  the  sun  ascends.  But  there  are  often  condi- 
tions, especially  in  winter,  under  which  it 
persists  through  the  day.  It  is,  in  general, 
more  frequent  in  winter  than  in  summer. 
But  on  the  Atlantic  and  Pacific  coasts  and  the 
shores  of  the  Great  Lakes,  the  parts  of  the 
country  in  which  it  is  most  frequent,  there  is 
more  of  it  in  summer  than  in  winter.  Of  the 
two  coasts  the  Pacific  has  more  of  it  than  the 
Atlantic  has.  Of  the  latter  the  New  England 
part  has  most;  and  of  the  former  the  middle 
California,  or  San  Francisco,  part  has  most. 

Evening  Clouds 

Much  of  the  thickness  that  so  often  appears 
on  the  horizon  at  evening  is  simply  smoke  or 
dust.     These  become  more  and  more  an  ac- 
205 


OUR   OWN    WEATHER 

cumulation  in  the  lower  air  toward  evening, 
because  then,  under  increasing  coolness,  the 
lower  air  has  less  and  less  circulation.  What 
of  this  thickness  is  not  smoke  and  dust  is  far- 
away fog.  But  there  is  apt  to  be,  at  evening, 
on  a  fair  day,  somewhat  above  the  horizon, 
a  sheet  of  cloud  of  the  general  stratus  type. 
It  may  be  strict  stratus — that  is,  a  strip  of 
lifted  fog.  Again,  it  may  be  a  strip  of  cloud 
formed  just  like  fog,  except  that  instead  of 
forming  directly  on  the  ground  it  has  formed 
on  a  layer  of  air  relatively  cold,  like  the  ground, 
from  a  warmer  layer  lying  on  top  of  it.  This 
condition  of  a  cool  or  cold  layer  of  air  under  a 
warmer  one  is  not  unusual  down  near  the 
ground  at  the  time  of  the  daily  cooling-off. 
Also  favorable  to  the  formation  of  evening 
clouds  is  the  afternoon  breaking-up,  with,  per- 
haps, some  settling  down  and  reformation, 
of  the  conditions  and  material  that,  through 
the  middle  of  the  day,  produced  the  cumulus 
clouds.  Often  the  midday  cumulus  clouds 
themselves,  under  some  pressure  above  and 
around  them,  instead  of  heaping  up  in  their 
more  ordinary  way,  spread  out  horizontally 
and  run  together  and  become  a  range  rather 
than  separated  piles,  and  even  smooth  out  into 
206 


CLOUDS    AND   SUNSHINE 

a  sheet.  This  might  very  well  mark  a  warmth 
in  the  air  above  that,  as  the  lower  air  cooled 
toward  evening,  would  produce,  lower  down, 
layers  of  evening  clouds.  The  evening  clouds 
are  apt  to  settle  lower  and  lower  as  the  cooling 
continues  and  to  disappear  soon  after  nightfall. 

The  Highest  Clouds 

There  are,  no  doubt,  clouds  formed  so  high 
up  in  the  sky  that  we  cannot  at  all  see  them. 
The  highest  of  all  are  the  cirrus — clouds  com- 
posed of  ice  particles;  and  of  them  the  highest 
that  we  do  see  are  so  far  away  and  so  thin  that 
they  do  not  show  as  clouds,  but  only  as  a 
peculiar  whiteness  of  the  sky.  Sometimes  the 
higher  ones  become  visible  only  as  rings,  or 
halos,  about  the  sun  or  the  moon  or  stars.  They 
are  not  rings  themselves,  but  thin  and  often 
wide-spread  veils,  and  the  rings  are  simply  a 
play  of  light  from  the  veiled  body  on  particles 
of  the  cloud. 

In  the  United  States  the  average  level  at 
which  cirrus  clouds  form  is  about  six  miles  in 
the  summer  half  of  the  year  and  about  five  in 
the  winter  half.  The  average  levels  of  forma- 
tion are  considerably  higher  for  all  classes  of 
clouds  in  the  United  States  than  in  Europe; 
207 


OUR   OWN    WEATHER 

and  for  all  classes  the  average  velocity  is  also 
considerably  greater  here  than  there.  The 
average  velocity  of  cirrus  clouds  here  is  about 
four  miles  an  hour  in  the  winter  half  of  the 
year,  but  only  a  little  more  than  half  that  in  the 
summer  half.  Thus,  while  the  height  is  greater 
in  summer  than  in  winter,  the  speed  is  less; 
and  this  is  true  not  only  of  cirrus,  but  of  all 
other  classes  of  clouds. 

In  both  height  and  velocity  the  cirrus  clouds 
often  immensely  exceed  their  average.  At  the 
kind  we  oftenest  see  one  must  look  with  some 
closeness  to  detect  that  they  have  any  move- 
ment. But  the  higher  cirrus  have  sometimes 
a  speed  of  anywhere  from  a  hundred  to  two 
hundred  miles  an  hour.  And  while  about  six 
miles  above  sea-level  is  their  ordinary  height, 
they  may  be  as  much  as  ten  miles  above  sea- 
level.  Their  formation  at  such  heights  gets  an 
added  interest  from  the  fact  that  any  kind  of 
condensation  of  water  vapor  in  the  air,  whether 
into  fog  or  cloud  or  rain,  is  a  collection  of  the 
vapor  on  particles  of  dust.  As  dust  gets  into 
the  air,  presumably,  only  from  the  earth,  the 
higher  clouds  are  a  mark  of  the  great  heights 
to  which  considerable  quantities  of  it  must  be 
carried. 

208 


CLOUDS    AND    SUNSHINE 

Thin  and  feathery  or  fibrous  strips  or  star- 
rings-out  or  veils  of  a  light  silver  hue,  and  with 
the  look  of  being  high  up  and  cold,  are  the 
general  forms  in  which  the  loftier  cirrus  cloud 
exhibits  itself.  Only  when  it  has  either  dropped 
down  somewhat  from  its  highest  levels  or 
formed  on  somewhat  lower  ones  does  it  yield 
the  images  of  fish-scales  and  horse-tails  by  which 
it  is  best  known.  It  may  then  even  be  not 
wholly  cirrus — not  wholly  ice-cloud — but  partly 
water-cloud.  It  sometimes  forms  in  the  undu- 
lations and  contacts  of  the  great  overflowing 
and  counterflowing  currents  of  the  general 
circulation  of  the  higher  atmosphere.  In  that 
case  it  has  no  connection  with  any  relatively 
brief  and  local  warming  and  cooling  at  or  near 
the  ground.  But  it  arises  as  well,  and  in  large 
quantities,  from  most  of  the  low-down  dis- 
turbances. 

The  topmost  part  of  the  manifold  cloud 
structure  of  a  thunder-storm  is  very  often  quite 
visibly  cirrus,  spreading  out  from  the  central 
point  of  the  storm,  somewhat  backward,  but 
farther  forward,  or  in  the  direction  the  storm 
is  traveling.  Also  there  is  always,  as  has  been 
already  explained,  cirrus  at  the  top  of  cyclones, 
spreading  from  the  center  of  these,  as  from  that 
209 


OUR    OWN    WEATHER 

of  the  thunder-storm,  somewhat  back,  but 
farther  forward,  and  giving  by  its  forward 
spread  a  from  one  to  two  days'  warning  of 
the  cyclone's  approach.  Cirrus  flowing  out 
from  and  beyond  a  cyclone  is  the  kind  we  most 
frequently  see.  Its  movement  is  eastward. 

Storm-clouds 

The  cirrus,  then,  in  its  more  familiar  forms  is 
always  a  storm-cloud.  A  storm  begets  it,  and 
its  appearance  is  an  announcement  either  that 
the  storm  is  coming  or  has  gone  by.  The  great 
spreads'  and  masses  of  storm-clouds  are,  how- 
ever, cumulus — exactly  the  same  in  composition 
and  manner  of  formation  as  the  bright,  serene 
bodies  that  are  the  ordinary  creation  and  token 
of  a  fair  day.  Let  the  conditions  that  produce 
these  bodies  be,  by  one  cause  or  another,  in- 
tensified in  some  limited  locality — the  moisture 
of  the  lower  air  increased,  and  its  warming-up 
and  ascension  and  cooling-off  all  quickened. 
Instead  of  comparatively  small,  inactive  clouds, 
formed  placidly  at  the  top  of  narrow,  slow-ris- 
ing columns,  there  will  arise  extended,  rapidly 
formed  volumes,  tending  to  intermingle  and  to 
conflict  with  each  other,  and  so  to  develop 
210 


CLOUDS    AND   SUNSHINE 

within  them  a  high  energy.  By  their  rapid 
growth  and  combination  they  will  occupy 
more  and  more  of  the  sky;  and  if  the  formation 
and  the  incident  conflict  become  intense,  there 
will  be  high  winds  and  finally  rain. 

Local  aggravations  of  the  ordinary  cloud  con- 
ditions occur  with  particular  ease  in  summer; 
and  when  they  are  strong  what  they  are  apt 
to  become  in  the  end  is  thunder-storms.  Even 
local  aggravations,  however,  are  apt  to  have 
their  origin  in  more  general  ones.  The  greater 
cloud  formations  are  always  due  to  cyclones. 
The  vast  areas  of  warm  moist  air  set  to  mov- 
ing northward  and  westward  by  the  draft  of  a 
cyclone  soon  begin  to  meet  with  cooler  areas, 
and,  partly  from  contact  with  these  and  partly 
through  being  forced  upward  by  them,  suffer 
a  cooling  that  produces  enormous  volumes  of 
clouds. 

Here  the  great  scale  on  which  the  business  is 
conducted  gives  the  product  often  a  very  differ- 
ent aspect  from  the  clear,  snowy  heaps  of  ordi- 
nary midday  condensation.  The  push  and 
pressure  of  the  great  cloud  masses,  their  high 
interior  energy,  and  the  rapid  variations — 
breaks  and  rises  and  falls — of  the  levels  of  con- 
densation combine  to  obscure  completely  out- 


OUR   OWN    WEATHER 

lines  and  movements,  and  often  all  we  see  is  a 
dull  spread  of  clouds  over  the  whole  sky, 
sometimes  thin,  sometimes  thick,  but  without 
distinguishable  form  or  character. 

Sometimes  in  a  given  region  the  whole 
affair  culminates  at  just  this  stage.  The  cy- 
clone's influence  in  that  region  begins  to  les- 
sen; the  spread  of  clouds  slowly  dissolves,  and 
so  the  disturbance  ends.  But  if  the  disturbance 
increases,  the  spread  of  clouds  is  apt,  without 
entirely  ceasing  to  be  a  spread,  to  thicken  up 
from  part  to  part,  with,  in  these  thick  parts, 
great  volumes  of  cloud  rolling  in  and  out.  At 
this  stage  the  more  projecting  portions  of  the 
mass  often  show  in  their  own  form  and  action 
some  resemblance  to  fair-weather  cumulus; 
and  the  entire  mass  is  of  the  same  general  con- 
stitution and  character.  All  the  clouds  formed 
or  provoked  by  a  cyclone,  except  the  cirrus 
formed  at  the  top  of  the  cyclone,  are  essen- 
tially cumulus. 

It  is  always  from  cumulus  clouds  that  rain 
falls,  but  from  cumulus  that,  under  the  special 
stress  and  pressure  of  its  formation,  has  be- 
come in  its  lower  part — the  part  from  which 
the  rain  falls  —  somewhat  more  dense  and 
stratus-like  than  ordinary  cumulus.  Because, 
213 


CLOUDS   AND   SUNSHINE 

though,  of  the  distinction  of  the  rain  the  rain- 
cloud  has  been  given  a  name  by  itself — that 
of  nimbus.  The  height  of  rain-clouds  varies 
from  two  hundred  feet  to  a  mile.  The  patches 
and  fragments  of  clouds  that  are  often  seen 
flying  wildly  just  under  a  rain-cloud  have  been 
allowed,  even  by  the  weather  authorities,  to 
retain  their  familiar  name  of  "scud." 

A  spread  of  clouds  tends,  in  the  fore  part  of 
the  day,  by  shutting  out  the  sunshine  and  thus 
lessening  the  warming-up  in  the  lower  air  and 
on  the  ground,  to  make  the  weather  cooler. 
And  it  tends,  in  the  latter  part  of  the  day,  to 
retard  the  escape  of  heat  from  the  lower  air  and 
from  the  ground,  and  so  to  make  the  weather 
warmer.  Under  a  cover  of  clouds  the  lower 
air  becomes  sometimes  very  still,  losing  much 
of  even  its  lighter  tremors  and  flutters.  If  it  is 
not  itself  murky  at  such  times,  we  have  a  con- 
dition that  is  the  most  favorable  of  any  for 
seeing  distant  objects.  They  can  be  seen  at 
such  a  time  with  a  clearness  far  greater  than  on 
any  cloudless  day.  But  every  day  at  the  times 
of  lull  in  the  ordinary  warming  and  cooling 
there  is  apt  to  be  produced  in  the  lower  air 
something  of  this  same  condition ;  and  the  time 
from  a  little  before  to  a  little  after  either  sunset 
213 


OUR   OWN    WEATHER 

or  sunrise  is  well  defined  as  more  favorable  than 
the  rest  of  the  day  for  clear  and  far  seeing. 
There  has  been  no  end  of  thought  and  labor 
expended  in  efforts  to  arrive  at  a  practical 
and  complete  classification  of  the  clouds. 
So  far  as  their  general  composition  and  their 
fundamental  method  of  formation  are  con- 
cerned, the  matter  was  very  well  worked  out  long 
ago.  But  the  circumstances  in  which  they  arise 
and  travel  and  dissolve  are  of  wellnigh  infinite 
variety;  and  so  they  are  themselves,  in  their 
actual  appearance  and  behavior,  probably  the 
most  variable  objects  on  which  the  eye  of  man 
ever  falls.  And  since  man  is  man,  this  makes 
them  to  him  also  one  of  the  most  fascinating 
objects  on  which  his  eye  ever  falls.  It  gives 
them  the  enticing,  infatuating  quality  of  mate- 
rialized spirits,  while  they  hold,  of  course,  over 
these  always  a  clear  advantage  in  the  matters 
of  reality  and  form.  Any  one  who  has  the  habit 
of  glancing  at  the  sky  and  the  clouds  is  sure  of 
at  least  one  delightful  moment  whenever  he 
steps  out-of-doors.  But  even  any  one  in  whom 
this  habit  is  only  casual  is  likely  to  become 
plagued  with  a  desire  to  pick  out  of  the  limit- 
less variability  and  dissimilarity  of  the  clouds 
every  possible  shred  of  likeness,  constancy,  and 
214 


CLOUDS    AND   SUNSHINE 

order.  And  this  is,  in  effect,  what  has  been 
aimed  at  in  the  later  endeavors  to  classify 
them. 

In  the  classification  most  accepted  ten  forms 
are  defined;  and  they  are  chosen  and  arranged 
on  the  principle  of  exhibiting  the  three  funda- 
mental kinds  of  clouds — cirrus,  cumulus,  and 
stratus — in  their  most  typical  stages  of  develop- 
ment, combination,  and  transition.  That  the 
primary  forms,  under  the  many  stresses  to 
which  clouds  must  be  constantly  subjected, 
make  all  sorts  of  conversions  of  themselves 
and  of  unions  with  each  other,  changing  from 
distinct  piles  or  strips  or  bands  into  veils  and 
sheets  and  areas  of  patches  or  of  tufts  and  balls, 
is  very  clear.  But  it  is  still  only  partially 
determined  how  these  changes  come  about  and 
what  they  severally  mean. 

The  Colors  of  the  Clouds  and  the  Sky 

For  their  varied  and  brilliant  colors  the 
clouds  and  the  sky  are  much  beholden  to  those 
foreign  substances  in  the  air  that  are  grouped 
under  the  name  of  "dust."  The  colors  are 
wholly  due  to  some  interruption  of  waves  of 
light  by  either  particles  of  dust  or  particles  of 
215 


OUR   OWN    WEATHER 

the  permanent  gases  of  the  air.  According  as 
the  interrupting  particles  are  large  or  small 
and  turn  back  or  break  up  or  scatter  about  the 
light  waves  in  one  direction  or  another,  with 
reference  to  the  observer,  one  or  another  color 
appears.  The  upper  parts  of  the  sky  are  blue, 
especially  when  looked  at  with  one's  back  to 
the  sun;  and  this  is  largely  because  the  upper 
air  is  freer  from  dust  than  the  lower  air  and 
the  dust  there  is  apt  to  be  of  finer  grain.  In 
the  lower  sky,  where  the  dust  is  both  coarser 
and  more  abundant,  the  blue  gives  place  to 
white.  Whether  low  or  high,  the  sky  is  more 
white  than  blue  when  we  look  toward  the  sun, 
because  especially  of  the  greater  directness 
with  which  the  light  then  comes  to  us.  The 
sun  itself,  because  simply  of  the  special  make- 
up of  the  medium  through  which  we  see  it, 
is  light  orange.  If  the  medium  were  entirely 
stripped  away  and  the  sun  seen  with  nothing 
of  the  atmosphere  before  it,  the  best  opinion  is 
that  it  would  be  blue.  The  sky,  on  the  other 
hand,  under  such  a  stripping,  would,  it  is 
thought,  be  black. 

Whenever,  from  any  cause,  the  air  is  dustier 
than  ordinary,  or  when  the  light  travels  through 
a  particularly  long  section  of  the  dustier  part, 
216 


CLOUDS    AND   SUNSHINE 

less  of  blue  and  white  and  more  of  the  strong 
colors,  like  yellow  and  red,  appear.  It  is  be- 
cause simply  of  the  sun's  shining  through  a 
greater  length  of  lower  air  at  sunset  and  sunrise 
than  during  the  rest  of  the  day  that  at  those 
times  the  sky  shows  a  special  abundance  of 
bright  colors.  Preceding  sunset  the  colors 
strengthen  as  the  sun  goes  down;  following 
sunrise  they  weaken  as  the  sun  rises. 

The  clouds  partake  of  the  general  color  of  the 
sky,  but  also  modify  it  more  or  less  according 
to  their  own  composition.  During  the  middle 
of  the  day  they  are  light  or  white  in  the  parts 
that  get  the  full  light  of  the  sun  and  gray  or 
blue  in  the  parts  that  are  shaded  from  it. 
With  the  sun  in  front  of  them,  and  so  at  the 
back  of  the  observer,  they  are  apt  to  show  bright 
in  the  central  part  and  darker  at  the  edges. 
But  when  the  sun  is  behind  them  it  is  at  the 
edges  that  they  are  likeliest  to  be  bright.  They 
appropriate  freely  of  the  general  strength  of 
color  in  the  evening  and  the  morning  sky, 
and  often,  like  great  geniuses  who  appropriate 
freely,  add  so  much  quality  and  grace  of  their 
own  as  to  get  credit  for  the  whole  creation. 

In  general,  the  high  clouds  are  lighter  than 
the  low  ones;  and  the  highest,  the  cirrus,  keep 
217 


OUR   OWN    WEATHER 

pretty  steadily  their  prevailing  hue  of  light 
silver.  When,  though,  a  veil  of  cirrus  makes  a 
halo  about  the  sun  or  the  moon,  the  light  of  the 
veiled  body  falls  on  the  ice  particles  of  the  cloud 
in  such  a  way  as  to  produce  not  only  a  ring,  but 
often  a  ring  of  the  brightest  colors,  red  inside 
and  blue  outside.  In  the  smaller  rings  known 
as  coronas,  which  also  are  produced  by  thin 
clouds  lying  over  the  sun  or  the  moon,  the 
cloud  particles  are  not  ice,  but  water,  and  when 
bright  colors  appear  the  blue  is  inside  and  the 
red  outside.  It  is  in  the  several  kinds  of  cumu- 
lus cloud  that  the  colors  are  exhibited  in  their 
greatest  range  and  brilliancy. 

The  incalculable  variety  and  splendor  of  the 
colors,  added  to  a  ceaseless  change  of  form, 
gives  the  clouds,  even  for  the  most  careless 
eye,  an  unmatched  and  limitless  magnificence. 
Moreover,  in  them  all  the  activities  and  inten- 
tions of  the  whole  system  of  the  weather  are 
bound  up  as  if  in  immense  decorated,  gold- 
clasped  books,  written  half  to  inform  and  half 
to  mystify.  No  wonder,  therefore,  that  we  can 
never  really  look  at  them  without  delight. 
The  only  wonder  is  that  of  our  delight  we  are 
so  often  not  conscious :  we  have  it  without  quite 
knowing  that  we  have  it. 
218 


CLOUDS    AND    SUNSHINE 

One  of  the  most  brilliant  of  the  color  spec- 
tacles of  the  sky  is  not  classed  as  a  weather 
product.  This  is  the  northern  lights,  or  aurora 
borealis.  It  is  an  illumination  caused  by  some 
sort  of  electric  discharge  with  which  weather 
conditions  have  not  been  found  to  have  any 
necessary  relation.  That  brilliant  creation, 
the  rainbow,  on  the  other  hand,  is  produced 
directly  by  the  weather.  It  is  akin  to  the  halo, 
and  is  caused  by  the  light  of  the  sun  falling 
on  drops  of  rain  in  the  air  in  just  the  right  way 
to  produce  an  arc  of  color.  Often  two  rainbows 
are  seen  at  once.  The  smaller  one,  which  is 
also  the  brighter,  is  made  by  light  entering  the 
upper  portion  of  the  drops.  In  it  the  outer 
edge  is  red  and  the  inner  edge  blue.  To  make 
the  larger  and  dimmer  one,  the  light  enters 
the  lower  portion  of  the  drops.  In  it  the  inner 
edge  is  red  and  the  outer  edge  blue.  Rain- 
bows form  sometimes  also  under  the  light  of 
the  moon. 

15 


XIII 

DEW    AND    FROST,    RAIN     AND    SNOW 

IT  has  been  calculated  that,  if  the  water 
vapor  ordinarily  afloat  in  the  atmosphere 
were  precipitated  all  at  once  in  the  form  of 
snow,  it  would  cover  the  entire  earth  to  a 
depth  of  twenty  inches.  In  its  transportation 
and  deposits  of  this  invaluable  element  the  at- 
mosphere deals  very  fairly  with  the  United 
States.  There  are,  to  be  sure,  a  few  parts  of 
the  country  that  might  complain  of  neglect, 
except  that,  while  they  get  little,  they  also  give 
little.  In  its  deliveries  of  moisture  the  atmos- 
phere but  returns  to  the  earth  what  it  has 
gathered  from  the  earth,  and  in  general  it  re- 
stores to  a  region,  and  at  times  of  special  need, 
about  in  proportion  as  it  has  received  from  that 
region. 

The  quality  of  timeliness  in  the  delivery  is  a 
most  important  one.     To  this  in  part,  as  well 
as  to  good  quantity,  is  it  due  that  the  United 
220 


DEW  AND  FROST,   RAIN   AND  SNOW 

States  as  a  whole  never  fail  of  a  sure  productive 
supply.  An  annual  average  rainfall — rainfall, 
in  weather  records,  includes  both  rain  and 
snow — of  not  less  than  twenty  inches  is  suffi- 
cient, if  seasonably  distributed,  for  agricultural 
production  without  irrigation.  Some  compara- 
tively small  parts  of  the  country  do  not  have 
even  that  much.  But  far  the  greater  portion 
of  it  has  an  average  annual  rainfall  of  from 
thirty  to  fifty  inches,  or  just  the  quantity  best 
suited  to  good  growth  and  good  living. 

Dew  and  Frost 

In  the  simplest  and  most  frequent  form  of 
precipitation,  that  of  dew,  the  atmosphere  not 
only  gives  back  moisture  to  the  earth,  but  also 
refuses  to  take  moisture  that  the  earth  is 
offering  it.  The  air,  cooling  at  night  by  con- 
tact with  the  ground,  deposits  its  surplus  mois- 
ture on  the  grass  and  leaves  and  whatever  other 
cold  surfaces  it  touches.  But  all  vegetation, 
under  the  law  and  force  of  its  own  circulation, 
is  all  the  time  expelling  moisture  through  its 
own  surfaces.  During  the  heat  of  the  day 
this  moisture  mainly  evaporates  into  the  con- 
tiguous air.  At  night,  however,  the  air,  being 


OUR   OWN    WEATHER 

cold,  cannot  receive  it,  and  it  condenses  where 
it  lies  directly  into  dew.  Dew  may  come, 
therefore,  as  well  from  the  ground  as  from  the 
air;  and  from  which  it  shall  come  most  will  de- 
pend on  the  conditions  of  the  particular  time 
and  place. 

All  dew-making,  indeed,  is  brief  and  local. 
Very  slight  and  limited  differences  of  condi- 
tion prevent  or  favor  it.  An  evening  or  night 
of  clear  sky  and  quiet  air  are  needful  to  it. 
A  spread  of  cloud  prevents  the  ground  and 
much  motion  prevents  the  air  from  cooling  to 
the  dew-point;  and  there  must  be,  either  from 
the  air  or  from  the  ground,  enough  moisture 
to  condense.  On  an  ordinary  dew-making 
night  the  dew  begins  to  fall  early  in  the  even- 
ing; but  the  heavier  part  of  the  fall  is  in  the 
latter  part  of  the  night,  a  little  before  sunrise. 

Frost  is  simply  dew  formed  when  the  tempera- 
ture is  at  or  below  freezing.  It  attracts  more 
attention  and  seems  a  much  more  important 
affair  because  of  the  harm  it  does  to  vegetation. 
Dew,  on  its  side,  does  an  equal  good,  no  doubt ; 
but  the  effect  is  less  visible.  Then,  the  frost  is 
always  driving  us  into  some  activity  in  order 
not  to  suffer  by  it.  With  the  dew,  we  have  only 
to  sit  still  and  receive  its  bounties. 


DEW  AND   FROST,   RAIN  AND  SNOW 

Frost,  quite  as  strictly  as  dew,  is  a  local  prod- 
uct. In  a  region  that  is  generally  liable  to  it, 
every  little  bit  has  its  own  liability  or,  maybe, 
its  own  immunity.  Exposed  hilltops  have  less 
of  either  frost  or  dew  than  have  valleys,  and 
for  the  curious  reason  that  the  air  on  hilltops 
tends,  as  it  cools  at  evening,  to  fall  away  under 
its  own  increased  weight  into  the  lower  lands 
and  there  make  its  condensations.  Dry  regions 
are,  as  a  rule,  just  those  in  which  there  are 
especially  clear  skies  and  a  strong  cooling-off 
at  night;  and  they  entirely  lack  frost  or  dew 
only  if  their  dryness  is  of  the  extremest  type. 
Either  frost  or  dew,  according  to  the  tempera- 
ture, on  every  clear,  still  night  is  the  rule  for 
nearly  the  whole  United  States,  but  with  in- 
numerable local  variations,  according  to  special 
exposures  and  protections. 

Since  a  temperature  down  at  least  to  freezing 
is  indispensable  to  the  formation  of  frost,  there 
is  a  seasonal  movement  north  and  south  in  the 
general  frost  area.  In  North  Dakota  and 
Minnesota,  that  coldest  of  all  corners  of  the 
country,  killing  frosts  occur  sometimes  in 
August;  but  usually  they  begin  there  about 
the  middle  of  September.  They  begin  nearly, 
but  not  quite,  as  early  in  some  parts  of  the 
223 


OUR    OWN    WEATHER 

Rocky  Mountain  and  plateau  regions.  In  all 
the  rest  of  the  country  they  rarely  occur  before 
October,  and  in  most  of  the  Southern  states 
rarely  before  November.  For  their  average 
time  of  leaving  off  in  the  spring  the  range  is 
from  the  middle  of  March  for  the  more  south- 
ern states  to  the  middle  of  May  for  the  more 
northern,  with  great  irregularity  in  the  west- 
ern mountain  and  plateau  regions.  There  are 
sometimes,  though,  strong  departures  from  the 
average.  Killing  frosts  have  occurred  near  the 
middle  of  June  in  localities  where  ordinarily 
they  are  entirely  over  by  the  first  of  May. 

The  Form  and  Habits  of  the  Rain 

We  speak  of  a  "fall"  of  dew;  but,  strictly, 
dew  never  falls.  Even  when  the  moisture  of  it 
comes  from  the  air  the  cold  surface  on  which 
the  condensation  occurs  is  a  part  either  of  the 
earth  or  of  something  attached  to  the  earth. 
But  in  fog  or  haze  or  clouds  or  rain  or  snow  the 
condensation  is  always  on  cool  dust  particles 
afloat  in  the  air.  So  with  any  of  these  an  actual 
fall  is,  as  it  is  not  with  dew,  possible.  It  is 
the  fixed  habit  of  rain,  simply  because  in  rain 
the  drops  are  comparatively  large  and  heavy. 
224 


I! 
II 


*  *! 

2;    g ' 


a    o 
o   j< 

d  l 


DEW  AND   FROST,   RAIN   AND  SNOW 

Impossible  as  at  first  glance  the  achievement 
might  seem,  raindrops  have  been  subdued  to 
definite  measurement.  Very  small  ones  are 
less  than  three  -  hundredths  of  an  inch  in  di- 
ameter. Very  large  ones  may  be  as  much  as 
three- tenths  of  an  inch.  Those  that  occur  with 
most  frequency  range  from  four  -  hundredths 
to  thirteen-hundredths  of  an  inch.  They  fall 
the  faster  in  proportion  as  they  are  larger. 
Large  drops  are  formed  partly,  if  not  wholly, 
by  the  coalescing  of  small  ones;  and  they  tend, 
as  they  fall,  to  break  up  again  into  small  ones. 
The  drops  are  not  hollow  but  are  coats  of  water 
enveloping  a  particle,  or  particles,  of  dust. 
Falling  from  such  heights  as  they  do,  only  the 
resistance  of  the  air  keeps  them  from  acquiring 
a  force  that  otherwise  would  be  destructive. 
Without  this  resistance  a  raindrop  from  a 
height  of  only  half  a  mile  would  become,  it 
has  been  said,  "as  dangerous  as  a  bullet." 
From  just  how  high  up  any  one  drop  ever  comes 
there  is  no  telling.  Often  the  clouds  from 
which  rain  is  falling  are  only  a  few  hundred 
feet  above  the  ground.  They  are  about  a  mile 
above  it  at  their  highest. 

The  rain,  in  its  fall,  washes  the  air  as  thor- 
oughly as  it  washes  the  ground.  A  special 
225 


OUR    OWN    WEATHER 

clearness  is  apt  to  mark  the  air  just  after  a 
strong  rain;  and  it  is  due  not  simply  to  the 
air's  lessened  moisture,  but  to  it's  having  been 
washed  free  of  dust.  Curious  things  are 
sometimes  brought  down  in  the  course  of  such 
a  cleansing:  things  caught  up  from  the  earth 
and  which  it  would  seem  that  the  air  could  not 
possibly  have  retained  for  the  time  or  in  the 
quantity  that  it  clearly  has.  Often  they  are 
identified  as  originating  in  regions  far  removed 
from  that  in  which  they  fall.  Occasionally, 
through  having  a  marked  color  and  falling 
with  great  profusion,  they  make  a  coat  on  the 
ground,  and  so  give  rise  to  stories  of  red  or  some 
other  whimsical  kind  of  rain. 

The  formation  of  rain  is,  in  general,  little 
more  than  the  formation  of  an  ordinary  cumulus 
cloud  carried  to  a  point  where  the  store  of  water 
in  the  cloud  becomes  so  great  that  some  of  it 
has  to  fall.  A  body  of  warm,  moist  air,  under- 
run  and  pushed  upon  by  a  body  of  dense,  dry 
air  becomes  so  cooled  under  the  mere  force  of 
its  struggle  to  rise  and  spread  out  that  it  must 
expel  or  condense  some  of  its  moisture.  Even 
as  cloud  the  condensed  moisture  is  heavier 
than  the  air,  but  so  little  so  that  a  very  slight 
upward  pressure  of  the  air  will  suffice  to  keep 
226 


DEW  AND   FROST,   RAIN  AND  SNOW 

the  cloud  afloat.  But  the  instant  it  exceeds 
the  normal  weight  of  cloud,  unless  the  upward 
movement  or  pressure  of  the  air  becomes  in  some 
way  equally  abnormal,  a  fall  of  some  portion 
of  the  moisture  is  inevitable. 

Occasionally  the  condensation  is  so  rapid  and 
intense  that  rain  is  formed  directly :  there  is  no 
cloud,  and  the  rain  falls  from  a  perfectly  clear 
sky.  And  occasionally,  when  the  lower  air  is 
very  warm,  rain  formed  above  evaporates  be- 
fore it  reaches  the  ground,  and  it  can  then  be 
seen  directly  overhead  and  no  drop  of  it  be 
felt.  Arizona  is  a  region  that  sometimes  ex- 
hibits this  phenomenon  with  extraordinary 
clearness.  With  us  very  much  the  largest  part 
of  the  rain  is  a  condensation  from  bodies  of 
warm,  moist  air  thrown  into  disturbance  by 
the  force  of  cyclones.  The  larger  number  even 
of  what  appear  as  simply  local  rains  are  due  to 
cyclonic  influence. 

So  much  of  an  inch,  or  so  many  inches  of 
rain  means  simply  that  rain  to  that  depth  has 
collected  in  a  measure  held  out  for  it  during  a 
given  time.  The  presumption  is  fair  that  the 
rain  fallen  to  the  ground  is  in  close  to  the  same 
proportion.  A  hundredth  of  an  inch  in  an  hour 
is  about  the  lightest  fall  that  occurs.  One  inch 
227 


OUR   OWN    WEATHER 

in  an  hour  is  violent.  But  in  hard  thunder- 
storms, and  especially  in  those  that  produce 
cloud-bursts,  we  sometimes  experience  falls 
many  times  greater  than  that.  There  is  record 
of  a  fall  of  eighteen  inches  in  an  hour.  The 
greater  of  the  sharp  falls  are  produced  only  in 
very  dry  times  or  in  very  dry  localities.  A  fall 
of  half  an  inch  in  a  day  is  heavy ;  but  falls  of 
an  inch  in  a  day  are  rather  frequent.  The  av- 
erage fall  on  a  single  day  is  only  two-hun- 
dredths  of  an  inch. 

There  is,  undoubtedly,  for  most  localities  a 
rainy  time  of  day.  It  has  not  much  value, 
though,  because  one  can  never  be  quite  sure 
what  it  is.  It  changes  more  or  less  from  season 
to  season  and  from  place  to  place,  and  even  in 
a  given  place  and  a  given  season  it  has  its 
variations.  At  most  places  in  the  United  States 
less  rain  is  to  be  expected  during  the  warming- 
up  part  of  the  day — say,  from  five  o'clock  in 
the  morning  until  two  in  the  afternoon — than 
in  the  rest  of  it.  But  as  between  afternoon  and 
night  the  division  is  apt  to  be  dim.  In  the 
greater  storms  rain  is  likely  in  any  part  of  the 
day.  In  even  the  rainiest  of  such  storms  much 
the  greater  part  of  the  rainfall  occurs,  however, 
within  the  limits  of  a  single  day — or  within, 
228 


DEW  AND   FROST,   RAIN   AND  SNOW 

that  is  to  say,  a  period  of  twenty-four  hours. 
The  highest  average  of  continuous  rainfall  in 
any  parts  of  the  country  is  six  hours.  This  is 
along  the  Atlantic,  Pacific,  and  Gulf  coasts. 

Over  nearly  the  whole  country  there  is  some 
amount  of  rain  or  snow  on  about  one-third  of 
the  days  of  the  year,  and  none  on  about  two- 
thirds  of  the  days  of  the  year.  The  only  impor- 
tant departures  from  this  average  occur  in  parts 
of  California  and  of  the  Rocky  Mountain  and 
plateau  regions,  where  the  average  number  of 
days  in  the  year  that  produce  any  rainfall  is 
considerably  less  than  a  hundred.  The  rainy 
days,  naturally,  are  considerably  fewer  every- 
where than  the  cloudy  days. 

Distribution  of  the  Rain  over  the  Country 

Naturally,  there  is  much  more  evaporation 
from  the  great  bodies  of  water  during  the  warm 
half  of  the  year  than  during  the  cold  half.  The 
air  has  in  it  over  most  of  the  country  several 
times  more  moisture  in  midsummer  than  in 
midwinter;  and  thus  in  most  parts  to  rain 
proves  rather  easier  in  summer  than  in  winter. 
Only  along  the  Pacific  coast  and  in  the  northern 
part  of  the  region  between  the  Sierra  Nevada 
229 


OUR   OWN    WEATHER 

and  the  Rocky  mountains  is  the  winter  half 
of  the  year  the  rainier  half.  In  both  of  these 
sections  the  air  that  bears  moisture  comes 
mainly  from  the  Pacific  Ocean.  In  summer 
it  is  warmed  by  contact  with  the  land ;  in  winter 
it  is  cooled.  In  winter,  therefore,  it  most  parts 
with  its  moisture.  Just  along  the  Pacific  practi- 
cally no  rain  falls  except  in  the  winter  half  of 
the  year.  It  begins  lightly  in  October,  comes 
to  its  greatest  in  December,  and  then,  diminish- 
ing gradually,  finishes  in  April.  It  amounts  to 
enough  to  make,  in  the  northern  half  of  the 
Pacific  coast  region,  an  annual  fall  of  from 
eighty  to  somewhat  over  a  hundred  inches, 
much  the  largest  annual  fall  in  any  part  of  the 
country  and  one  of  the  largest  in  all  the  world. 

The  other  of  the  two  sections  in  which  winter 
rains  prevail  has  a  somewhat  even  distribution 
through  all  but  just  the  summer  months.  Its 
whole  annual  fall,  however,  is  small,  nowhere 
more  than  twenty-five  inches  and  in  some  parts 
scarcely  more  than  ten.  It  comprises  the  state 
of  Idaho,  the  eastern  parts  of  Washington  and 
Oregon,  and  the  northern  parts  of  Utah  and 
Nevada. 

The  southern  parts  of  Utah  and  Nevada 
unite  with  western  Arizona  and  southeastern 
230 


DEW  AND   FROST,   RAIN  AND  SNOW 

California  to  make  the  region  of  least  rainfall 
of  any  in  the  country.  The  record  established 
here  in  the  dryest  part  must,  indeed,  at  least 
equal  any  on  the  face  of  the  earth.  It  amounts 
practically  to  no  rainfall  whatever.  The  more 
favored  parts  have  an  annual  fall  of  eight  or 
nine  inches.  Most  of  it  occurs  high  up  on  the 
sides  of  the  mountains  and  is  largely  in  the  form 
of  snow. 

In  eastern  Arizona,  New  Mexico,  and  western 
Texas,  where  the  annual  fall  is  from  fifteen  to 
twenty  inches,  about  a  third  of  it  comes  rather 
evenly  divided  between  the  months  of  July  and 
August.  All  the  other  months  get  some,  but 
May  and  June  the  least. 

In  all  the  country  from  the  Rocky  Mountains 
to  the  Mississippi  River  and  north  of  Texas 
every  month  in  the  year  has  an  appreciable 
rainfall,  but  the  larger  part  is  in  the  latter  half 
of  spring  and  the  first  half  of  summer.  It  is 
especially  in  this  region  that  the  value  of  the 
fall  lies  largely  in  its  timeliness.  Through  all  of 
the  western  half  of  the  region  the  annual  fall 
is  scant — from  fifteen  to  twenty-five  inches; 
and  if  it  did  not  come,  as  it  does,  mainly  in 
the  planting  and  growing  season  many  a  wide 
area  that  is  now  highly  productive  would  be 
231 


OUR    OWN    WEATHER 

barren.  Through  the  other  (the  eastern)  half 
of  the  region  the  rainfall  is  ample — from  twenty- 
five  to  thirty  inches  for  the  year. 

For  the  country  from  the  Mississippi  River 
eastward  the  annual  fall  ranges  from  thirty  to 
fifty  inches;  and  the  twelve  months  share  in 
it  almost  equally.  The  summer  months  lead, 
but,  as  a  rule,  not  largely.  There  are  practically 
no  dry  months. 

Snow  and  Its  Fall  and  Distribution 

Rain,  at  its  formation,  is  of  a  temperature 
somewhere  above  freezing.  But  it  is  often 
reduced  to  a  temperature  below  freezing  by 
being  carried  through  masses  of  cold  air.  In 
such  a  case  it  may  turn  directly  into  ice  and 
make  the  rest  of  its  fall  and  reach  the  ground  as 
sleet — that  is,  as  grains  of  ice,  and  not  as  drops 
of  water.  But,  instead,  it  may  reach  the  ground 
cold  enough  to  freeze,  yet  still  unfrozen;  and 
then  it  becomes  on  whatever  cold  surfaces  it 
lands,  such  as  those  of  buildings,  streets,  or 
trees,  a  coat  of  ice.  When,  however,  at  the 
first  formation  the  vapor  condensed  is  itself  of 
a  coldness  equal  to  freezing  the  product  is, 
not  rain,  but  snow;  and  between  rain  and  snow 
232 


DEW  AND  FROST,   RAIN   AND  SNOW 

this  is  the  only  essential  difference.  Snow  also 
is  sometimes  turned  into  sleet,  and  because  in 
its  fall  it  is  not,  like  rain,  cooled,  but  warmed. 

Snow  is  always  a  greater  wonder  to  us  than 
rain,  mainly,  no  doubt,  because  of  its  com- 
parative infrequency,  but  certainly  in  part 
because  of  its  bright  and  varied  play  as  it  is 
coming  down.  Also  because  of  this  last,  snow, 
at  its  fall,  is  always  enlivening,  whereas  a  fall 
of  rain  often  is  not.  Even  in  large  cities, 
where  only  a  few  inches  of  snow  insure  several 
days  of  obstruction  and  nastiness,  people  feel 
their  spirits  coming  into  a  certain  gaiety  the 
moment  a  fall  begins. 

Of  its  various  graces  the  snow  holds  what  is 
perhaps  the  one  most  curious,  not  quite  open  to 
instant  sight.  This  is  the  beautiful  and  mani- 
fold forms  it  takes  in  its  crystallization.  Every 
single  flake,  if  not  injured  in  its  fall,  shows  an 
orderly,  intricate,  lovely  pattern;  and  yet  all 
are  different.  Thousands  of  them  have  been 
accurately  photographed  and  then  minutely 
compared,  and  never  are  any  two  alike.  They 
exhibit,  though,  enough  of  rule  and  resemblance 
to  content  somewhat  the  human  propensity  to 
classify  things.  It  has  been  determined  that 
there  are  general  kinds  peculiar  some  to  small 
233 


OUR   OWN    WEATHER 

flakes,  some  to  large,  and  some  to  flakes  falling 
in  one  or  another  of  the  four  quarters  of  a  cy- 
clone. 

Made  up  as  the  snow  is  of  outspread,  feathery 
bodies,  and  not  of  compact  pellets,  it  has  a 
slower  fall  than  the  rain.  But  the  fall  is  more 
rapid  according  as  the  flakes  are  smaller  and 
harder;  and  because  of  a  prevailing  difference 
in  just  this  the  falls  are  apt  to  be  more  rapid 
in  the  middle  of  winter  than  at  either  end  of 
it.  The  range  possible  is  well  marked  by,  on  the 
one  hand,  the  big  soft  flakes  that,  especially 
in  early  spring,  come  gently  down,  to  melt  per- 
haps at  their  first  touch  with  the  ground,  and, 
on  the  other  hand,  the  driving  ice  needles  that 
give  such  painfulness  to  the  midwinter  blizzard. 
Snow  has  about  ten  times  the  bulk  of  rain,  and 
it  is  customary  in  measuring  falls  to  regard 
ten  inches  of  snow  as  the  equivalent  of  an  inch 
of  rain.  In  the  eastern  part  of  the  country  the 
heaviest  falls  occur,  like  the  heaviest  falls  of 
rain,  in  connection  with  cyclones  from  the 
southwest. 

Southern   California,    just   along   the  coast, 

and  southern  Florida  are  the  only  parts  of  the 

country  that  never  have  snow.     The  greatest 

falls  are  in  the  Sierra   Nevada   and  Cascade 

234 


DEW  AND   FROST,   RAIN   AND  SNOW 

mountains.  They  amount  to  from  three  hun- 
dred to  four  hundred  inches  in  the  course  of  a 
year.  Large  falls  are  usual  also  in  various  parts 
of  the  Rocky  Mountain  region — falls  of  from 
one  hundred  to  more  than  two  hundred  inches 
a  year.  East  of  the  Rocky  Mountains  and 
across  the  more  northern  part  of  the  country 
the  average  annual  snowfall  is  fifty  inches. 
Upper  Michigan  makes  an  exception  by  show- 
ing in  some  districts  an  annual  fall  of  more  than 
a  hundred  inches.  There  is  a  gradual  lessening 
southward.  Through  the  Gulf  and  south  Atlan- 
tic states  the  average  for  the  year  is  five  inches. 
Great  individual  falls  occur  only  in  the  North. 
But  they  occur  in  the  East  as  well  as  the  West, 
and  one  of  the  greatest  of  them  reached  its 
highest  severity  in  and  around  New  York, 
where  it  is  kept  in  eminent  memory  as  "the 
great  March  blizzard  of  1888."  The  range  of 
such  falls  is  from  eight  to  thirty-six  inches, 
falling  within  a  period  of  twenty-four  hours. 
Those  of  the  largest  type  are  much  oftener 
reported  than  seen.  A  three-foot  snow,  a  five- 
inch  rain,  and  an  eighty-miles-an-hour  wind, 
while  offered  to  us  never  but  as  wonders,  still 
are  offered  with  some  frequency,  owing  to  the 
play  of  temperament  in  reporters.  Weather 
16  235 


OUR   OWN    WEATHER 

Bureaus  put  their  confidence,  therefore,  only 
in  instruments. 

Hail-storms 

In  the  midst  of  thunder-storms  we  often  get 
what  is  neither  rain  nor  snow,  but  yet  has  un- 
mistakable snow  embedded  in  it.  This  is  hail. 
The  hail-stones,  which  are  more  or  less  dis- 
torted balls  made  up  of  layers  of  ice  and  snow, 
show  that  they  must  have  been  formed  where 
the  air  was  cold  and  in  violent  whirl.  They 
vary  much  in  shape  and  also  in  size.  Just 
before  a  fall  of  hail  begins  the  air  below  is  apt 
to  show  an  extraordinary  closeness.  It  freshens 
rapidly  as  the  fall  progresses.  Coming  usually 
but  as  part  of  a  thunder-storm,  hail -storms 
come  mainly  in  summer.  They  are  rare  in 
winter,  and  they  are  rare  also  at  night.  A  par- 
ticularly sultry  summer  afternoon  is  the  time 
that  seems  most  to  invite  them.  They  are 
never  of  wide  extent,  and  they  are  apt  to  be 
repeated  in  localities  that  favor  them. 

Droughts  and  Floods 

Rainfall,  like  all  the  other  elements  of  the 
weather,  has  its  excesses,  both  of  abundance  and 
236 


DEW  AND  FROST,   RAIN  AND  SNOW 

deficiency.  Those  involving  single  regions  or 
sections  are  rather  frequent.  Every  year  is 
apt  to  produce  one  or  more  of  them.  But  those 
extending  over  a  great  part  of  the  country  are 
rare,  and  become  historic.  Eminent  among 
such  is  a  drought  that  began  in  1893  and  did 
not  wholly  finish  until  1895  and  that  affected  all 
the  country  from  the  Rocky  Mountains  to  the 
Atlantic  Ocean.  Yet  the  total  crop  production 
of  the  country  did  not  fall  during  those  years 
greatly  below  the  normal.  The  smaller  droughts 
are  often  more  damaging,  within  their  limits, 
than  the  large.  They  sometimes  last  with 
full  intensity  two  or  three  months.  The  latter 
half  of  spring  and  the  first  half  of  summer, 
the  parts  of  the  year  in  which  for  most  of 
the  country  the  rainfall  is  greatest,  are  like- 
wise the  parts  in  which  droughts  are  most 
common  and  also  most  harmful.  An  interest- 
ing fact  in  connection  with  droughts  is  that 
they  are  apt  to  be  immediately  preceded  by 
a  particularly  heavy  fall  of  rain. 

Of  floods  the  greatest  ones  arise  when  warm 
winter  storms  produce,  along  with  heavy  falls 
of  rain,  a  thawing  out  of  large  accumulations 
of  ice  and  snow.  This  is  a  condition  that  some- 
times occurs  in  the  early  part  of  January,  at 
237 


OUR   OWN    WEATHER 

which  time  winter  has  a  habit  of  letting  go  its 
hold  for  a  week  or  two  in  order  only  to  take  a 
stronger  and  longer  one.  The  habit  is  not  con- 
stant nor  well  defined;  but  it  has  answered 
to  make  belief  quite  general  in  what  is  known 
as  the  January  thaw.  An  enormous  flood  is, 
however,  a  danger  offered  much  more  by 
February  or  March  than  by  January,  and  by 
the  complete  than  by  a  partial  break-up  of 
winter. 

The  greatest  flood  we  can  possibly  have  is 
one  that  involves,  as  occasionally  one  does  in- 
volve, the  entire  basin  of  the  Mississippi  River, 
an  area  of  1,240,050  square  miles.  The  greater 
Mississippi  River  floods  come  usually  in  just 
one  way.  They  begin  in  the  lower  Mississippi, 
where  all  the  bordering  country  is  flat  and  low, 
under  the  passage  of  a  series  of  heavy  rain- 
storms arising  in  the  Southwest.  The  rain- 
fall may  not  be  much  above  what  is  normal  for 
the  place  and  time  of  year,  but  it  suffices  to 
raise  the  waters  of  the  lower  Mississippi  nearly 
or  quite  to  the  danger-line. 

The  storms,  one  close  after  another,  travel 

on  from  the  Mississippi  northeastward.     They 

continue  to  produce  heavy  falls  of  rain,  and 

by  their  warmth  they  produce  also  a  general 

238 


DEW  AND  FROST,   RAIN  AND  SNOW 

thaw  in  the  snow  and  ice  laden  mountainous 
regions  of  West  Virginia  and  western  Penn- 
sylvania. The  result  is  a  great  flood  in  the 
Ohio  River.  This  is  soon  added  to  the  one 
already  too  well  begun  in  the  Mississippi. 
Under  the  addition  the  Mississippi  flood  not 
only  heightens  and  widens  southward,  accord- 
ing to  its  natural  flow,  but  also  backs  northward 
into  the  upper  Mississippi.  It  may  back  vol- 
uminously enough  to  spread  even  into  the 
mouth  of  the  Missouri  River.  If  now,  under 
the  break-up  of  winter  in  the  North  and  the 
Northwest,  individual  floods  are  added  from  the 
Missouri  River  and  the  upper  Mississippi,  the 
inundation  becomes  one  of  inconceivable  im- 
mensity, and  it  injures  in  proportion  to  its 
magnitude. 

A  flood  of  this  description  may  occupy  as 
much  as  three  months  in  its  building-up  and 
dispersion.  At  the  places  most  exposed  to  it 
the  waters  may  rise  to  as  much  as  eight  or  ten 
feet  above  the  danger -line,  and  may  remain 
at  some  such  height  for  as  long  as  a  month. 
And  it  all  comes  about  in  a  manner  so  easy  and 
simple,  so  without  real  abnormalities,  that  we 
might  almost  expect  it  to  occur  every  year 
instead  of,  as  it  does,  once,  say,  in  four  or  five 
239 


OUR   OWN    WEATHER 

years.  What  saves  us  is  that,  while  all  of  the 
conditions  for  one  of  these  mammoth  floods 
arise  in  greater  or  less  degree  every  winter  or 
spring,  some  chance  keeps  them  from  arising 
with  just  the  continuity  or  simultaneousness 
needful  to  produce  one.  It  is  a  chance  for  which 
we  may  well  be  thankful. 

The  lesser  floods  occur  with  much  more  fre- 
quency, and  they  often  do  much  damage.  But 
all  the  damage  they  do,  and  even  all  that  the 
great  ones  do,  is  not  enough  to  make  the  people 
of  any  part  of  the  country  want  to  give  up  either 
their  rivers  or  their  rain-storms. 


XIV 

THUNDER-STORMS  AND  TORNADOES 

THUNDER-STORMS  always  come  sudden- 
ly, pass  quickly,  and  are  limited  each  to  a 
comparatively  small  region.  They  might  seem, 
therefore,  to  be  a  kind  of  vagary  of  the  weather. 
When  they  occur  in  winter,  which  is  but  rarely, 
they  do  mark  a  departure  from  the  ordinary 
course  of  things.  It  is  not,  however,  so  in  sum- 
mer. Then  they  are  as  definite  a  part  of  the 
regular,  the  systematic  weather  as  are  cyclones 
and  anticyclones.  And  they  have  in  both  winter 
and  summer  a  close  relation  to  these. 

The  large  amount  of  heat  and  moisture  in 
the  air  in  summer  keeps  it  at  that  season  pe- 
culiarly well  prepared  for  quick  overturnings. 
The  descent  of  a  body  of  colder  air  instantly 
sets  things  off.  The  sharpness  of  the  conflict 
provokes  electrical  discharges,  made  apparent 
in  lightning  and  thunder,  and  provokes  also 
strong  dashes  of  wind  and  rain.  The  amount 
241 


OUR   OWN    WEATHER 

of  rain  produced  is,  considering  the  small  ex- 
tent of  the  storms  themselves,  notably  large. 
The  larger  part  of  the  rain  of  the  year  comes 
from  cyclones.  But  the  larger  part  of  the  rain 
of  the  summer  half  of  the  year,  which  is  rather 
the  rainier  half,  comes  from  thunder-storms. 

For  their  bounty  in  this  the  thunder-storms 
cannot,  however,  take  the  entire  credit.  They 
themselves  are  largely  the  creations  of  cyclones. 
They  might,  indeed,  be  described  as  the  cy- 
clone's preferred  way  of  producing  rain  in 
summer.  It  is  mainly  under  the  atmospheric 
movements  set  up  by  cyclones  that  the  bodies 
of  cold  air  descend  and  begin  to  root  out  the 
bodies  of  hot  air  with  the  abruptness  that  makes 
thunder-storms.  Many  occur  that  have  no  ap- 
parent relation  to  a  cyclone;  but  they  are  only 
of  the  smallest  and  briefest  kind.  For  any 
but  the  more  casual  and  momentary,  the  usual 
order  of  the  business  in  the  country  east  of 
the  Rocky  Mountains  is  this : 

The  Spread  of  a  Thunder-storm  Epidemic 

A  cyclone  starts  across  the  country  by  the 
northern  track,  the  one  by  which  most  of  the 
cyclones  go  in  summer.     According  to  the  habit 
242 


THUNDER-STORMS  AND  TORNADOES 

of  cyclones  following  that  track,  especially  in 
summer,  it  produces  about  its  center  little  or 
only  moderate  rain.  But  at  some  distance 
from  the  center  the  bodies  of  air  moving  toward 
the  cyclone  raise  a  condition  that  results  in  an 
outbreak  of  thunder-storms.  Within  a  limited 
region  there  will  be  a  number  of  them  all  on 
the  same  day.  The  outbreak  may  occur  any- 
where from  two  hundred  to  nine  hundred  miles 
away  from  the  center  of  the  cyclone.  Once 
begun,  the  infection  spreads  eastward  in  clear 
correspondence  with  the  eastward  progress  of 
the  cyclone  itself.  Sometimes  the  spread  is 
continuous,  but  sometimes  it  is  by  leaps  from 
region  to  region,  one  receiving  it  full  strength 
and  breaking  into  storms,  and  another  remain- 
ing entirely  immune  and  suffering  not  even 
showers.  The  general  disturbance  ceases  in 
region  after  region  according  as  the  cyclone 
travels  away;  and  it  continues  in  any  one 
region  never  more  than  two  or  three  days. 

The  outbreaks  occur  sometimes  to  the  south- 
west of  the  center  of  the  cyclone,  and,  more 
rarely,  to  the  northwest.  In  both  of  these 
quarters  the  storms  come  almost  wholly  in 
either  the  late  afternoon  or  early  evening. 
They  are  always  small  and  brief,  and  never 
243 


OUR    OWN    WEATHER 

travel  far;  but  those  in  the  northwest  are  apt 
to  be  violent.  Much  the  greater  number  of 
outbreaks,  however,  occur  to  the  southeast  of 
the  cyclone  center,  and  the  large  thunder- 
storms arise  only  in  this  one  quarter.  Here  the 
storms  often  come  in  the  morning,  but  still 
not  as  often  as  in  the  late  afternoon  and  early 
evening.  From  four  o'clock  of  the  afternoon 
until  eight  o'clock  of  the  evening  is  the  pre- 
ferred part  of  the  day  with  all  classes  of  thunder- 
storms. 

All  thunder-storms  travel.  The  small  ones 
are  able  to  achieve  only  quite  short  distances 
before  they  expire,  and  they  keep  to  no  general 
direction,  for  they  are  entirely  controlled  by 
the  movements  of  the  lower  air  and  the  con- 
tour of  the  ground  over  which  they  travel. 
But  the  large  ones  extend  up  into  the  air  some 
thousands  of  feet;  and  they  are,  on  this  ac- 
count, carried  forward  by  the  general  move- 
ment of  the  upper  air,  and  have  usually  a  course 
from  southwest  to  northeast.  Some  rotation 
in  the  storm  itself,  however,  causes  it  in  most 
instances  to  show  in  its  actual  descent  upon  a 
given  place  as  coming  from  the  west.  The 
large  ones  often  travel  as  far  as  two  or  three 
hundred  miles.  The  ordinary  rate  of  travel  is 
244 


THUNDER-STORMS  AND  TORNADOES 

from  twenty-five  to  thirty  miles  an  hour,  but 
occasionally  one  has  a  speed  of  as  much  as 
forty  miles  an  hour. 

Thunder-storms  range  in  size  about  as  they 
range  in  the  length  of  their  courses.  The  small 
ones  may  be  in  breadth  less  than  a  mile,  and 
the  large  ones  as  much  as  three  hundred  miles. 
The  front  of  the  storm  bows  inward,  so  that 
the  edges  travel  somewhat  in  advance  of  the 
center.  The  small  storms  are  often  scattered 
by  the  irregularities  of  the  land;  but  the  large 
ones  often  cross  high  mountains  without  break- 
ing up.  Sometimes  one  is  split  by  a  mountain, 
and,  working  round  it,  part  on  one  side  and  part 
on  another,  travels  on  as  two  storms.  But 
occasionally  in  such  a  case  the  two  parts  after 
passing  the  mountain  come  together  again. 

' '  H eat ' '  Thunder-storms 

The  thunder-storms  that  have  no  connection 
with  cyclones  often  occur,  like  the  others,  in 
considerable  numbers  at  about  one  time,  and 
all  within  a  certain  district.  While  the  storms 
themselves  are  always  small  and  travel  only 
short  distances,  the  district  within  which  they 
are  grouped  may  be  of  considerable  extent.  It 
may  comprise,  say,  an  entire  state.  But  there 
245 


OUR   OWN    WEATHER 

is  no  succession  of  districts,  no  moving  on  of 
the  thunder-storm  condition  from  district  to 
district,  which  is  so  marked  in  thunder-storms 
attendant  on  cyclones.  The  little  storms  burst- 
ing forth  for  a  scant  half -hour  here  and  there  are 
simply  the  break-up  of  an  extreme  sultriness 
established  in  a  single  region.  They  are  known 
as  "heat"  thunder-storms,  and  the  name  suits 
well  with  their  character.  They  occur  almost 
always  in  the  afternoon,  at  or  soon  after  the 
culmination  of  the  daily  warming-up. 

The  thunder-storm  has  a  particular  interest 
because  we  are  permitted  to  see  so  much  of  it. 
Like  the  cyclone,  it  sends  out  a  herald  in  the 
form  of  a  forerunning  sheet,  or  cover,  of  cirrus 
cloud.  The  fringy  front  edge  appears  some- 
times as  much,  as  two  hours,  or  fifty  miles,  in 
advance  of  the  main  body  of  the  storm.  As  the 
sheet  gradually  spreads  the  lower  air,  which  has 
been,  perhaps,  extremely  close,  begins  to  freshen. 
In  due  time  there  begin  to  push  up  from  the 
horizon,  usually  in  the  west,  ominous  dark 
piles  of  cumulus  clouds  of  a  kind  that  have  come 
to  be  known,  because  of  their  heavy  rounded 
tops,  as  "thunder-heads."  They  may  be  as 
much  as  an  hour's  journey  away  when  they 
first  appear.  When  they  have  advanced  about 
246 


THUNDER-STORMS  AND  TORNADOES 

half  of  that  distance  the  thunder  is  apt  to  be- 
gin. Ten  or  twelve  miles  is  about  the  farthest 
reach  of  thunder. 

As  the  heavy  dark  clouds  ascend  they  dis- 
close a  level  base,  with,  hanging  down  from  it, 
a  sheet  of  lighter  clouds  from  which  the  rain 
comes.  The  lightning  becomes  more  frequent 
and  vivid  as  the  storm  gets  near.  The  first 
actual  strike  of  the  storm  is  in  the  form  of  vio- 
lent wind  that  sets  everything  flying.  Then 
comes  the  rain,  first  in  large,  scattered  drops, 
then  in  a  dense  downpour.  The  rain  and  the 
wind  and  the  lightning  all  increase  together, 
and  then  together  begin  to  lessen.  The  rain  is 
apt  to  quicken  immediately  after  a  particularly 
sharp  stroke  of  lightning.  It  usually  somewhat 
outlasts  the  wind  and  the  more  vivid  lightning. 
The  thunder  comes  sounding  back  even  after 
the  storm  has  gotten  entirely  by. 

The  fall  of  rain  in  thunder-storms  is  apt  to 
be  great  for  the  size  of  the  storm,  and  the  small 
storms  are  apt  to  have  greater  falls  in  propor- 
tion to  their  size  than  the  large  ones.  There 
often  comes  from  a  single  thunder-storm  what 
would  amount,  for  its  locality,  to  a  good  fall 
of  rain  for  a  month.  It  is  in  thunder-storms 
mainly  that  those  tremendous  downpours  known 
247 


OUR   OWN    WEATHER 

as  ' '  cloud-bursts  "  occur.  They  are  well  named, 
for  the  spill,  besides  being  enormous,  is  con- 
fined to  a  small  area  and  is  all  accomplished  in 
a  very  short  time.  They  often  cause  in  their 
one  little  region  a  great  destruction. 

The  Lightning  in  Thunder-storms  and  Its  Fatality 

Considerable  destruction  is  wrought  also  by 
the  winds  in  thunder-storms.  But  their  most 
fearful  element  is  the  lightning.  We  always 
feel  this  when  we  are  in  the  presence  of  a 
thunder-storm,  and  at  such  a  time  our  sense 
of  it  is  apt  to  exceed  our  danger.  Divided  up 
among  all  the  people  and  all  the  places,  the 
liability  to  a  stroke  of  lightning  becomes  very 
small;  quite  small  enough,  in  fact,  for  the  poetic 
application  we  often  make  of  it  to  politicians 
whose  expectations  exceed  their  outlook.  But 
it  is  still  enough  of  a  liability  to  make  entire 
disregard  of  it  utter  foolhardiness. 

An  average  of  more  than  three  hundred  peo- 
ple are  killed  in  the  United  States  in  the  course 
of  a  year  by  lightning.  This  is  somewhat 
larger,  in  proportion  to  population,  than  the 
number  of  deaths  by  lightning  in  most  parts 
of  Europe,  where  also  thunder-storms  are  fre- 
248 


THUNDER-STORMS  AND  TORNADOES 

quent,  though  as  a  rule  of  less  extent  and  in- 
tensity than  with  us.  In  two  parts  of  Europe 
— namely,  Prussia  and  the  Austrian  Alps — the 
number  is,  however,  somewhat  larger  than  in 
the  United  States.  Of  the  damage  done  to 
property  by  lightning  there  are  no  really  close 
or  complete  estimates.  It  must  amount,  though, 
in  the  United  States  for  an  average  year  to  a 
loss  of  several  million  dollars. 

The  distribution  of  damage  and  fatalities 
among  the  different  parts  of  the  country  cor- 
responds somewhat,  but  not  closely,  to  that 
of  thunder-storms  themselves.  All  parts  oc- 
casionally have  such  storms;  but  they  are  ex- 
tremely rare  in  California,  and  are  frequent 
nowhere  on  the  Pacific  coast.  They  are  fairly 
frequent  through  the  Rocky  Mountain  and 
plateau  regions.  But  they  are  more  frequent 
everywhere  east  of  the  Rocky  Mountains  than 
anywhere  in  them  or  west  of  them,  except  in  New 
Mexico  and  Arizona,  where  the  number  is  some- 
what greater  than  to  the  north  and  west.  There 
are  about  twice  as  many,  though,  in  the  south- 
ern half  of  the  country  east  of  the  Rocky 
Mountains  as  in  the  northern  half;  and  of  all 
the  eastern  country  the  part  that  has  fewest 
is  New  England. 

249 


OUR   OWN    WEATHER 

The  nearer  and  only  dangerous  lightning  is 
that  which  appears  as  vivid  darts  and  streaks 
or,  with  great  rarity,  as  vivid  balls.  The  sheet, 
or  "heat,"  lightning  is  not  the  direct  flash,  but 
a  diffused  reflection  produced  by  clouds.  It 
appears  only  at  some  distance,  and  often  at  so 
great  a  distance  that  no  thunder  is  heard 
after  it. 

The  Weather  Bureau  has  sought  to  ascer- 
tain if  different  soils  have  a  different  liability  to 
lightning  strokes,  and  the  information  thus  far 
gathered  indicates  that  they  have.  The  liabil- 
ity is,  apparently,  somewhat  greater  for  loamy 
soil  than  for  sandy  soil,  and  considerably  greater 
for  either  of  these  than  for  clay  soil.  Every- 
day experience  long  ago  discovered  a  difference 
in  this  particular  among  trees,  and  the  dis- 
covery is  confirmed  by  recent  scientific  inquiry. 
The  safest  tree  to  fly  to  in  a  thunder-storm  is, 
unquestionably,  the  beech ;  and  by  far  the  most 
dangerous  is  the  oak. 

Another  thing  recent  scientific  inquiry  has 
done  is  to  restore  to  the  lightning-rod  something 
of  the  trust  which  it  once  so  fully  held  and  then 
later  entirely  lost.  The  best  opinion  now  is 
that  a  lightning-rod  is  a  real  protection  if  you 
are  careful  to  have  a  good  one,  but  that  good 
250 


THUNDER-STORMS  AND  TORNADOES 

ones  are  not  to  be  had  without  care.  The  re- 
habilitation extends,  therefore,  only  to  the 
lightning-rod  itself,  not  to  the  old-time  light- 
ning-rod peddler. 

The  Tornado 

In  clean,  concentrated  violence  no  other 
storm  matches  the  tornado.  The  West  Indian 
hurricane,  even  modified  as  it  is  apt  to  be  when 
it  reaches  us,  proves  sometimes  a  mammoth 
destroyer,  and  it  ranks  properly  as  our  severest 
kind  of  storm.  But  its  immense  harmfulness 
is  due  to  the  fact  that  it  has  a  wide  reach  and 
long  endurance  as  well  as  high  intensity.  The 
tornado,  on  the  contrary,  is  always  small  and 
brief.  A  few  hundred  yards  is  its  usual  width; 
its  greatest  is  only  from  one  to  two  miles.  Its 
very  longest  journey  does  not  exceed  two  hun- 
dred miles.  Often  it  travels  only  a  mile  or  two, 
and  usually  but  twenty-five  or  thirty  miles. 
And  as  it  has  a  speed  of  from  twenty-five  to 
forty-five  miles  an  hour,  its  force  is  apt  to  be 
felt  at  any  one  place  for  less  than  a  minute. 
But  so  tremendous  is  this  force  that  anything 
the  tornado  touches  is  torn  instantly  to  pieces. 
No  other  type  of  storm  is  so  generally  destruc- 
tive and  fatal. 

17  251 


OUR   OWN    WEATHER 

Tornadoes  may  occur  in  any  part  of  the 
country  and  at  any  season;  but  they  are  most 
frequent  in  the  states  bordering  on  either  the 
Mississippi  River  or  the  Gulf  of  Mexico,  and 
they  come  oftenest  in  the  spring  and  early 
summer.  They  usually  arise,  like  the  greater 
number  of  thunder-storms,  in  the  southeast 
skirts  of  a  cyclone,  several  hundred  miles  from 
the  center.  They  are  often  themselves  called 
cyclones,  and  they  have  this  much  of  the  cy- 
clone's character,  that  they  are  bodies  of  air 
in  a  regular  whirl  from  right  to  left.  The  whirl 
is  rapid,  and  this  adds  to  their  destructiveness. 
They  liken  themselves  to  thunder-storms  again 
by  coming  sometimes  in  clusters,  and  also  by 
adhering  in  their  progress  to  the  general  di- 
rection of  the  cyclones  on  which  they  are  attend- 
ant from  southwest  to  northeast.  They  occur 
in  the  afternoon  or  evening,  and  always  under 
some  condition  of  extreme  sultriness. 

Just  how  tornadoes  are  provoked  has  not 
been  fully  determined.  This  much,  however, 
seems  to  be  certain:  that  large  bodies  of  air, 
pressing  forward  from  different  quarters  toward 
the  center  of  a  cyclone,  run  up  against  each 
other  and  fall  into  a  profound  tangle,  and  that 
this  embroilment  organizes  the  tornado.  The 
252 


THUNDER-STORMS  AND  TORNADOES 

organization  is  extraordinarily  compact  and 
well  defined.  At  a  little  distance  the  whole 
thing  is  easily  seen.  It  shows  as  a  funnel- 
shaped  trail  of  dark,  whirling,  fearful-looking 
cloud  hanging  straight  down  from  a  body  of 
the  same  frightful  aspect.  Its  small  lower  end, 
now  drawn  up  and  now  darted  down,  inter- 
mittingly  licks  the  ground.  The  storm  ad- 
vances with  a  terrific  rumble  or  roar.  Always 
a  few  minutes  ahead  of  it  there  is  a  dash  of 
rain;  and  in  the  midst  of  it  there  is  apt  to  be 
extraordinary  lightning  and  a  heavy  fall  of 
extremely  large  hail.  Because  of  its  curious 
ascents  and  descents  it  will  in  one  locality  do 
harm  only  some  feet  above  the  ground  and 
in  another  blast  the  whole  face  of  it. 

Three  or  four  a  year  is  estimated  to  be  the 
average  number  of  injurious  tornadoes  in  the 
United  States,  and  a  million  dollars'  worth  the 
average  annual  destruction  of  property  by 
them.  But  the  harmfulness  of  them  depends 
greatly  on  the  populousness  and  development 
of  the  region  over  which  they  sweep.  When 
one  descended  upon  the  city  and  environs  of 
St.  Louis  some  years  ago  it  destroyed  within 
half  an  hour  about  thirteen  million  dollars' 
worth  of  property  and  three  hundred  and  six 
253 


OUR   OWN    WEATHER 

lives.     Yet  it  was  not  in  itself  a  tornado  of  the 
greatest  severity. 

In  any  harmful  tornado  to  loss  of  property  is 
usually  joined  some  loss  of  life.  In  thirteen, 
occurring  within  a  period  of  twenty-one  years, 
the  lives  lost  amounted  to  twelve  hundred  and 
thirty-five.  The  smallest  number  lost  in  any 
one  of  them  was  forty-six;  and  in  every  one 
except  four  the  number  lost  exceeded  seventy. 
One  of  these  tornadoes  occurred  in  Georgia. 
All  the  others  occurred  in  the  Mississippi 
valley;  two  of  them  in  a  single  state,  Missouri, 
and  three  in  a  single  state,  Iowa. 

The  Great  Tornadoes  and  Floods  of  1913 

Just  as  these  pages  were  going  to  press  there 
occurred  a  series  of  tornadoes  that  caused  a 
greater  loss  of  human  life  than  ever  resulted 
before  at  any  one  time  from  tornadoes  in  the 
United  States.  And  in  immediate  connection 
with  them  came  a  series  of  floods  which  seem 
at  this  writing  likely  to  prove  also  one  of  the 
most  fatal  disasters  of  their  kind  that  the  coun- 
try has  ever  experienced. 

On  the  night  of  Thursday,  March  20,  1913, 
a  general  storm,  or  cyclone,  central  over  Lake 
254 


THUNDER-STORMS  AND  TORNADOES 

Michigan,  provoked  tornadoes  to  the  south 
and  southeast  of  it,  from  which  loss  of  life  re- 
sulted in  seven  or  eight  different  states.  Much 
the  severest  loss  was  in  the  state  of  Alabama, 
where  the  number  of  people  killed  was  one 
hundred  and  three.  Fatalities  in  neighboring 
states  brought  the  total  number  up  at  least  to 
one  hundred  and  forty. 

The  cyclone  itself  produced  through  the 
whole  of  its  general  course  only  light  rains; 
and  it  showed  in  no  way  as  being  in  itself  of 
unusual  force  until  it  crossed  Lake  Michigan. 
From  there  on  until  it  reached  the  St.  Law- 
rence valley  it  exhibited  in  the  winds  directly 
attendant  upon  it  a  record-breaking  intensity. 
Winds  blowing  at  the  rate  of  eighty-eight  miles 
an  hour  were  recorded  at  Detroit,  Michigan, 
and  at  Buffalo,  New  York. 

At  evening  on  Sunday,  March  23d,  three  days 
after  the  first  outbreak  of  tornadoes,  came  a 
second,  which  was  yet  more  destructive.  Of 
this  the  greatest  severity  was  felt  at  Omaha, 
Nebraska.  It  is  estimated  that  in  that  city 
and  its  neighborhood  not  fewer  than  two  hun- 
dred people  were  killed.  Next  to  Omaha,  the 
place  that  suffered  most  was  Terre  Haute, 
Indiana,  where  twenty  were  killed.  There 
255 


OUR   OWN    WEATHER 

were  fatalities  also  at  a  number  of  other  places, 
and  the  whole  number  of  lives  lost  in  the  second 
set  of  tornadoes  was  probably  not  less  than 
three  hundred.  This,  added  to  those  lost  in 
the  first  set,  makes  a  total  of  not  less  than  four 
hundred  and  forty. 

Previous  to  this,  the  highest  record  of  loss 
of  life  in  tornadoes  in  the  United  States  was 
four  hundred  and  sixteen  lives  lost  in  tornadoes 
occurring  in  groups  of  different  dates,  but  all 
in  the  one  month  of  May,  1896.  It  was  as 
one  in  this  succession  that  the  great  St.  Louis 
tornado  came,  and  the  lives  lost  in  it  alone 
numbered  three  hundred  and  six.  The  Omaha 
tornado  would,  therefore,  seem  to  have  been 
in  itself  not  as  bad  as  the  St.  Louis  tornado. 
But  the  series  to  which  it  belonged  shows  as 
considerably  severer  than  any  preceding  series. 

The  cyclone,  or  general  storm,  which  pro- 
voked the  Omaha  and  other  tornadoes  on 
March  23d  did  not,  like  the  one  that  produced 
those  of  March  2oth,  develop  extraordinary 
velocity  in  its  own  immediate  winds.  But  it 
did  produce  along  its  path  extraordinary  falls 
of  rain,  especially  in  Indiana  and  Ohio.  The 
streams  in  those  two  states  were  already  run- 
ning fairly  full  because  of  abundant,  though  not 
256 


THUNDER-STORMS  AND  TORNADOES 

exceptional,  rains  from  a  number  of  preceding 
storms.  The  sudden  addition  to  their  waters 
from  this  one  of  the  23d  brought  them  all  to 
flood. 

The  floods  grew  rapidly  the  next  day — Mon- 
day, the  24th — under  the  advance  of  yet  an- 
other general  storm,  a  narrow,  slow-moving 
trough  reaching  from  Texas  northeastward  to 
Lake  Erie,  and  producing  torrents  of  rain  in 
just  the  localities  where  more  was  surest  to 
prove  disastrous.  The  dawn  of  Tuesday, 
March  25th,  disclosed  to  the  world  that  Ohio 
and  Indiana  were  under  an  inundation  of  an 
extent  and  severity  such  as  not  those  localities 
certainly,  and  perhaps  none  in  the  whole 
country,  had  ever  before  experienced.  The 
calamity  is  at  present  lying  on  the  afflicted 
communities  so  deep  that  there  is  as  yet  no 
possibility  of  measuring  it.  But  the  loss  of 
life  and  property  resulting  from  it  cannot  fail 
to  be  enormous. 

Since  the  country  most  subject  to  tornadoes 
grows  all  the  time  more  populous,  the  fear  is 
sometimes  expressed  that  their  fatality  may 
greatly  increase.  There  is  some  solace  to  this 
fear,  perhaps,  in  the  fact  that  Prof.  Cleveland 
Abbe  has  ascertained  by  careful  calculations 
257 


OUR   OWN    WEATHER 

that  "even  in  the  so-called  tornado  states"  the 
probability  that  any  one  of  a  hundred  areas 
of  qne  square  mile  each  will  be  struck  by  a 
tornado  is  "less  than  one-fourth  of  one  per 
cent,  per  century."  The  reassurance  of  this 
would,  of  course,  be  greater  if  there  were  any 
telling  beforehand  just  which  area  was  to  get 
the  scarcely  ever  to  be  expected  stroke. 


XV 

WEATHER   SIGNS   AND   SUPERSTITIONS 

THE  Weather  Bureau  has  its  severities, 
like  the  weather  itself,  and  one  of  them 
is  the  coldness  with  which  it  looks  upon  the 
prophets  who  tell  us  what  the  weather  will  be 
for  a  month  or  a  season  or  even  for  a  whole 
year.  Many  of  us  find  these  prophets  very 
companionable,  though  we  may  not  give  them 
our  entire  trust.  If  they  were  suppressed,  as 
sometimes  the  more  scientific  predictors  seem 
to  think  they  should  be,  the  household  almanac 
would  become  a  sad  compilation,  for  its  jokes 
are  much  less  enlivening  than  its  weather 
predictions. 

The  Moon  and  the  Weather 

The  "long-range"  forecasters  all  make  much 

of  the  planets.     This  helps  to  put  us  in  awe  of 

them,  but  is  not  what  most  attaches  us  to 

them.     The  planets  are  so  far  off  and  show  so 

259 


OUR   OWN    WEATHER 

small  that  we  do  not  of  ourselves  have,  under 
the  sight  of  them,  a  constant  sense  that  they 
must  exert  an  influence  on  the  earth.  We  do 
have  this  sense,  however,  in  regard  to  the  moon; 
and  where  the  "long-range"  forecasters  really 
engage  us  is  in  upholding  with  their  own  our 
lingering  faith  in  the  moon  as  a  weather- 
breeder.  And  in  this  faith  even  the  true 
meteorologists  give  us  at  least  a  negative  sup- 
port. They  do  not  contend  that  the  moon  has 
no  influence  on  the  weather;  they  insist  only 
that  of  such  influence  no  clear  evidence  yet 
appears. 

There  is,  of  course,  no  disputing  the  fact  that 
at  what  we  call  the  changes  of  the  moon  no 
greater  change  occurs  than  at  other  times; 
that  the  changes  of  the  moon  are  even  and 
continuous,  and  consist  simply  in  its  beginning 
as  a  new  moon  and  increasing  night  by  night 
up  to  fullness,  and  then  as  steadily  night  by 
night  waning  until  it  passes  from  sight.  And 
this  does  impair  the  validity  of  some  of  the 
time-honored  moon  maxims.  But  many  of 
these  maxims  still  enjoy  a  wide  affection  and 
even  a  wide  belief,  as,  for  example,  the  fol- 
lowing : 

There  will  be  fair  days  and  fair  nights  for 
260 


SIGNS   AND   SUPERSTITIONS 

three  days  before  full  moon  and  for  four  days 
after  full  moon. 

When  the  moon  comes  in  at  midnight,  or 
within  thirty  minutes  before  midnight,  the 
weather  will  be  for  a  month  following  invari- 
ably fine. 

A  promise  akin  to  this,  but  for  a  shorter  pe- 
riod, is :  Within  the  limits  of  ten  o'clock  and  two 
o'clock  at  night,  the  nearer  midnight  the  moon 
changes  any  of  its  quarters  the  fairer  the 
weather  will  be  during  the  next  seven  days. 
And  within  the  limits  of  ten  o'clock  and  two 
o'clock  of  the  daytime,  the  nearer  midday  it 
changes  the  worse  the  weather  will  be  during 
the  next  seven  days. 

If  the  new  moon  lies  on  its  back,  and  so  will 
hold  water,  it  will  be  a  dry  moon.  Little  rain 
will  fall  while  it  lasts.  But  if  it  lie  tipped  for- 
ward so  that  the  water  must  spill,  it  will  be  a 
wet  moon.  It  is  only  another  expression  for 
the  same  adjustment  that  makes  the  dry  new 
moon  one  on  which  the  hunter  might  hang  his 
powder-horn  without  risk  of  its  either  slipping 
off  or  getting  wet. 

It  is  largely  the  charm  of  the  idea  that  makes 
us  still  cherish  such  maxims;  and  this,  no 
doubt,  has  also  much  to  do  with  our  holding 
261 


OUR   OWN    WEATHER 

on  to  the  fancy  that  birds  and  plants  and 
animals  enjoy  a  greater  prescience  in  the 
weather  than  we  do  ourselves.  And  perhaps 
this  is  true ;  nobody  positively  knows.  At  any 
rate,  we  find  it  pleasing  to  think,  for  example, 
that  squirrels  and  their  kind  lay  up  in  autumn 
a  greater  or  less  store  of  food ;  that  fur-bearing 
animals  thicken  or  thin  their  coats,  and  birds 
their  plumage,  and  trees  their  moss  and  bark, 
and  nuts  their  shells,  and  vegetables  their  husks 
and  rinds ;  and  that  birds  make  their  migrations, 
and  hibernating  animals  seek  or  leave  their 
dens,  all  in  a  sure  foreknowledge  of  the  mildness 
or  severity  of  the  coming  season.  There  is 
attraction  even  in  signs  that  have  less  plausi- 
bility than  these,  as  that:  If  the  rabbit  sits  up 
particularly  straight,  or  if  the  wasps  build  their 
nests  loose  on  the  ground,  or  if  the  apples  fall 
from  the  trees  in  quantities  rather  than  a  few 
at  a  time,  the  winter  will  be  mild;  and  if  the 
leaves  hang  to  the  trees  late  in  autumn  there 
will  be  much  snow. 

But  perhaps  the  most  precious  to  us  of 
all  the  traditions  regarding  weather  foresight 
in  the  animals  is  that  of  the  ground-hog,  or 
woodchuck,  and  his  behavior  on  the  second  of 
February,  or  Candlemas  Day: 
262 


SIGNS   AND   SUPERSTITIONS 

If  Candlemas  Day  be  bright  and  clear, 
We'll  have  two  winters  in  the  year. 

It  is  just  the  kind  of  dinning  couplet  that, 
once  received  into  the  memory,  nothing  but 
death  can  remove ;  and,  generation  after  genera- 
tion, we  have  all  gotten  it,  never  the  rest  of  our 
lives  to  get  rid  of  it.  With  the  larger  number 
of  Americans  it  probably  embodies  their  entire 
knowledge  of  Candlemas  Day;  but  this  little 
•they  hold  good  and  tight.  Generations  may  yet 
come  that  will  not  know  the  couplet ;  that  may, 
perhaps,  be  too  feeble  in  mere  verbal  memory, 
which  is  now  much  deprecated,  to  acquire  it. 
Yet  even  they,  limited  creatures  though  they 
may  be,  will  have,  one  must  believe,  still  some 
joy  in  the  ground-hog.  The  second  of  Feb- 
ruary will  not  pass  without  their  demanding 
gleefully  of  one  another  whether  the  ground- 
hog came  out  of  his  hole;  whether,  if  he  did 
come  out,  he  got  to  see  his  shadow,  and  whether, 
having  seen  it,  he  went  back  to  remain  housed 
until  the  second  winter,  which  he  knew  must 
come,  had  certainly  passed. 

Ever  to  remain  dear  to  us  is  also  the  maxim 
— not,  though,  an  animal  maxim  except  by  the 
grace  of  metaphor — that  if  March  comes  in 
263 


OUR   OWN    WEATHER 

like  a  lamb  it  will  go  out  like  a  lion,  and  if  it 
comes  in  like  a  lion  it  will  go  out  like  a  lamb. 

Men  and  Things  as  Barometers 

However  great  or  small  the  gift  of  animals, 
birds  or  plants,  or  even  men,  in  foretelling  the 
weather  for  long  periods,  they  all  have  in  their 
own  feeling  some  good,  true,  practical  premo- 
nitions of  it  for  a  day  or  two.  To  changes 
in  the  air  that  envelops  them  they  are  all 
more  or  less  sensitive,  and  they  betray  this 
sensitiveness  in  their  aspect  and  actions.  For 
ourselves,  sometimes  an  hour  or  two,  and  some- 
times two  or  three  days,  in  advance  of  a  storm 
we  begin  to  remark  that  the  air  is  growing  close 
and  heavy.  It  is,  in  fact,  growing  open  and 
light;  it  is  lessening  in  weight,  or  pressure. 
The  clear,  cool  air,  the  air  under  which  we  feel 
lively,  is  the  heavy  air,  the  air  of  high  pressure. 
But  because  warm,  moist  air  tends  both  to  over- 
heat the  body  and  at  the  same  time  to  repress 
it  in  its  readiest  means  of  relieving  itself  of 
excessive  heat,  that  of  evaporation  from  the 
surface,  we  often  find  such  air  sorely  oppressive. 

The  weather  is  marked  to  us  only  occasional- 
ly in  this  clear  way.  But  we  are  at  all  times 
264 


SIGNS    AND   SUPERSTITIONS 

as  responsive  to  variations  in  the  quality  of  the 
air  as  the  barometer  itself.  Men,  it  has  been 
observed,  eat  better,  sleep  better,  and  work 
better  when  the  barometer  is  high  than  when 
it  is  low.  When  the  barometer  falls  we  grow 
limp  in  body  and  endurance,  and  become  par- 
ticularly conscious  of  all  of  our  chronic  ailments 
and  weaknesses. 

Since  all  things  animate  as  well  as  inanimate 
have  somewhat  of  the  same  sensibility,  the 
face  of  the  earth  is,  we  might  say,  one  con- 
tinuous spread  and  thicket  of  weather  signs. 
And  the  reading  of  these  signs,  often  a  shrewd, 
often  a  crude  reading,  has  produced  an  endless 
store  of  homely  weather  maxims.  Because  of 
increasing  humidity,  smoke  falls  to  the  ground, 
noises  become  loud,  windows  and  doors  cling 
to  their  frames,  leaves  of  plants  freshen,  leaves 
of  books  stick  together,  odors  grow  stronger, 
stones  sweat,  fiddle-strings  lengthen,  and  no 
end  of  similar  things  occur  in  advance  of  rain; 
and  their  opposites  follow  it.  Further,  in  token 
of  the  rain's  coming  swallows  certainly  fly  low, 
and,  not  so  certainly,  perhaps,  cats  carry  their 
tails  up  and  rub  their  ears,  sheep  lie  about  in 
the  pasture  and  refuse  to  nibble,  hogs  grow 
restless  and  grunt,  roosters  flap  their  wings, 
265 


OUR   OWN    WEATHER 

hens  nestle  and  flutter  in  the  dust,  and  bees 
stay  close  in  their  hives. 

Clearly,  it  is  a  body  of  wisdom  of  unequal 
value.  Many  of  the  maxims  comprised  in  it 
are  true,  many  are  partly  true,  and  many  are 
not  true  at  all.  The  barometer  itself  is  in  the 
end  the  only  exact  barometer. 

The  Barometer  Signs 

Because  the  weather  is  so  largely  the  product 
of  the  long,  orderly  movements  of  cyclones  and 
anticyclones  the  general  behavior  of  the  barom- 
eter is  rather  simple.  It  shows,  as  a  rule, 
great  changefulness  only  at  or  near  the  center 
of  storms.  When  an  anticyclone,  a  fair-weather 
area,  is  in  full  control  of  a  region  the  barometer 
will  stand  at  something  above  thirty  inches, 
say  30. 10  or  30. 20.  It  will  stay  in  about  this 
position  some  days  if  the  anticyclone  is  not  a 
hastening  one.  But  as  the  anticyclone  begins 
definitely  to  move  away  there  will  begin  in  the 
barometer  a  gradual  fall. 

If  following  the  anticyclone  there  should  be, 

as  there  usually  is,  a  cyclone,  or  stormy  area, 

the  barometer  will  continue  to  fall  and  at  a 

steadily  quickening  rate.     As  soon  as  the  center 

266 


SIGNS    AND    SUPERSTITIONS 

of  the  cyclone  passes  the  fall  will  cease  and 
there  will  begin  a  rapid,  steady  rise.  But  for 
places  at  or  near  the  center  there  is  likely  to 
be,  as  the  center  passes,  first  a  brief  rise  and 
then  a  brief  fall  before  the  final  steady  rise 
sets  in. 

If  now  another  anticyclone  is  coming  forward 
the  rise  of  the  barometer  will  continue,  though 
at  a  steadily  lessening  rate,  until  the  center  of 
the  anticyclone  arrives  and  the  fair-weather 
mark  of  30.10  or  30.20  is  again  reached.  But 
if,  as  sometimes  happens,  instead  of  an  anti- 
cyclone another  cyclone  follows,  the  barometer 
will  stop  in  its  rise  somewhere  short  of  the  fair- 
weather  mark  and  begin  a  new  fall,  and  there 
will  be  repeated  for  the  second  cyclone  exactly 
the  movements  that  occurred  before  and  after 
the  first. 

The  barometer  behaves  in  a  local  storm  about 
as  it  behaves  in  a  general  one.  For  several 
hours  in  advance  of  a  thunder-storm,  for  ex- 
ample, it  maintains  a  steady  fall.  But  it  sud- 
denly rises  a  few  points  at  about  the  first  out- 
burst of  the  stronger  storm -winds.  There  it 
pauses  somewhat,  then  again  falls  a  little,  and 
then  with  the  first  lessening  of  the  storm  begins 
a  continuous  rise. 

18  267 


OUR   OWN    WEATHER 

This,  then,  is  the  barometer's  general  habit: 
It  stands  at  about  30.10  or  30.20  inches  during 
established  fair  weather.  It  maintains  a  steady 
fall  when  the  weather  is  changing  from  fair 
to  stormy,  and  a  steady  rise  when  the  weather 
is  changing  back  again  to  fair. 

As  the  barometer  falls  in  advance  of  a  storm 
the  temperature  generally  rises.  After  the 
storm  has  begun,  or  about  the  time  it  ends, 
the  barometer  begins  to  rise  and  the  tempera- 
ture to  fall.  But  sometimes  the  temperature 
remains  high  when  the  barometer  is  rising.  In 
that  case  there  is  likely  soon  to  be  another 
storm.  We  get  especially  clear  illustrations  of 
this  in  thunder-storms,  which  so  often  come 
one  close  after  another. 

The  more  rapid  the  changes  of  the  barometer 
in  any  circumstances,  the  more  quickly  and 
strongly  will  follow  the  changes  of  weather 
which  it  foretells.  A  gradual  fall  during  a  num- 
ber of  fair  days  indicates  not  only  a  change, 
but  a  change  embracing  a  number  of  wet  days. 
A  continuous  rising  in  wet  weather  indicates, 
on  the  other  hand,  that  after  a  day  or  two  there 
will  be  a  number  of  days  of  fair  weather.  Often, 
especially  in  the  general  storms,  a  region  lying 
at  some  distance  from  the  storm  center  feels 
268 


SIGNS    AND   SUPERSTITIONS 

the  storm  without  just  getting  it.  In  such  a 
case  there  may  be  a  considerable  fall  of  the 
barometer  without  marked  change  in  the 
weather. 

When  the  Rain  Begins 

It  is  interesting  and  also  useful  to  know  at 
what  marking  of  the  barometer  the  rain  or 
snow  from  a  coming  storm  is  likely  to  begin. 
One  of  the  many  valuable  bulletins  issued  for 
general  information  by  the  Weather  Bureau 
gives,  in  substance,  this  instruction: 

In  storms  from  the  southwest  or  south — 
storms  that  are  usually  indicated  by  winds 
blowing  from  points  between  east  and  north — 
the  fall  of  rain  or  snow  begins  with  the  begin- 
ning of  the  fall  of  the  barometer.  In  storms 
from  the  west  and  northwest  there  is  at  most 
places  a  fall  of  the  barometer  to  as  low  as 
29.90  or  29.80  inches  before  the  rain  or  snow 
begins.  But  along  the  south  Atlantic  and 
Gulf  coasts  the  fall  of  rain  or  snow  in  both 
classes  of  storms  begins  as,  or  nearly  as,  the 
fall  of  the  barometer  begins.  In  winter  this  is 
the  rule  also  around  the  Great  Lakes  and 
through  the  region  between  the  Rocky  Moun- 
tains and  the  Mississippi  River.  In  summer, 
269 


OUR   OWN    WEATHER 

though,  these  regions  have  the  rule  of  most  of 
the  other  parts  of  the  country,  and  in  west  and 
northwest  storms  rainfall  begins  only  after  the 
barometer  has  gotten  low. 

The  Wind  as  a  Warning  of  the  Weather 

vFor  the  greater  changes  in  the  quality  of  the 
air  we  hardly  need  to  read  the  barometer.  We 
can  learn  of  them  simply  by  our  own  feeling. 
In  the  same  way  and  by  looking  about  a  little 
we  can  learn  fairly  well  the  movement  of  the 
wind,  which  is  also  a  matter  of  importance  in 
forecasting  the  weather.  At  the  rear  of  an 
anticyclone,  or  fair-weather  area,  and  in  front 
of  a  cyclone,  or  stormy  area,  the  winds  are 
prevailingly  from  the  east.  In  advance  of  an 
anticyclone  and  at  the  rear  of  a  cyclone  they 
are  prevailingly  from  the  west.  But  within 
the  two  general  divisions  of  east  and  west  the 
direction  varies  from  point  to  point  north  or 
south  according  to  the  region  and  the  mo- 
mentary state  of  the  weather.  The  following 
general  rules  in  regard  to  the  matter  all  have 
the  indorsement  of  the  Weather  Bureau : 

Northeast  winds  indicate  rain  or  snow,  and 
they  often  indicate   "the  severest  storms  to 
270 


SIGNS   AND   SUPERSTITIONS 

which  a  great  part  of  the  United  States  is  sub- 
ject." 

Southeast  winds  are  rain-winds,  but  indicate 
storms  less  violent  than  are  indicated  by  north- 
east winds. 

Northwest  winds  indicate  general  clearing  and 
fair  weather,  and  they  are  usually  cool  or  cold. 

Southwest  winds  also  indicate  fair  weather, 
and  they  are  usually  warm. 

Over  a  great  part  of  the  United  States  a 
steady  and  strong  south-to-east  wind  will 
bring  rain  within  thirty-six  hours. 

Soon  after  the  wind  in  a  storm  shifts  from  an 
eastern  quarter  to  a  western  quarter  the  weather 
will  begin  to  clear. 

The  final  shift  of  the  wind  into  the  west  or 
the  northwest,  under  which  we  get  colder 
weather,  is  apt  to  be  a  sudden  shift.  Colder 
weather,  therefore,  comes  as  a  rule  suddenly; 
but  warmer  weather  comes  gradually. 

Cloud  Signs 

Clear  and  often  early  warning  of  changes  of 

the  weather  is  given  by  the  clouds.     The  high, 

silvery  cirrus  clouds  appear  in  advance  of  the 

central  part  of  a  cyclone,  or  general  storm,  any- 

271 


OUR   OWN    WEATHER 

where  from  eighteen  hours  to  two  days.  They 
appear  also  in  advance  of  a  local  storm,  but 
never  more  than  a  few  hours.  They  show  at 
first  as  strands  or  wisps  or  feathery  strips  or 
patches.  They  gradually  thicken  into  a  cloak 
or  cast  covering  most  of  the  sky. 

The  cirrus  clouds  make  the  "mackerel 
scales  and  mare's  tails"  that  time  out  of  mind 
have  prompted  "lofty  ships  to  carry  low  sails" 
in  expectation  of  a  storm.  Their  movement  is 
eastward  and  almost  always  from  some  point 
between  northwest  and  southwest.  The  higher 
they  are  in  the  sky  the  slower  the  approach,  but 
also  the  greater  the  extent  of  the  storm  move- 
ment they  foretell. 

But  cirrus  clouds  are  not  always  a  warning 
of  storm;  for  they  trail  out  also  somewhat 
backward  from  the  larger  storms,  and  they 
often  form  high  up  in  the  sky  quite  above  the 
lower  storm  region.  Then,  when  they  forerun 
a  storm,  they  sometimes  extend  farther  than 
the  rain  or  snow  from  the  storm  will  reach. 
Especially  after  a  long  period  of  dry  weather 
are  cirrus  clouds  no  sure  promise  of  rain. 

But  then  all  signs  of  rain  fail  in  dry  weather. 
The  familiar  maxim  is  perfectly  true :  the  signs 
do  appear,  and  yet  the  rain  does  not  come. 
272 


SIGNS    AND    SUPERSTITIONS 

Storms  do  not  wholly  cease  in  dry  weather; 
but  they  are  apt  to  be  weak,  and  in  addition 
they  cannot  in  their  travels  find  moisture 
enough  in  the  atmosphere  to  make  a  rain. 
They  can  only  start  a  southerly  wind  and  raise 
clouds  and  our  hopes  of  rain. 

In  regard  to  cloud  warnings  of  the  weather, 
some  of  the  best  approved  instructions  are: 

If  streaks  of  cirrus  point  upward,  the  clouds 
are  falling  and  rain  is  indicated;  if  they  point 
downward,  the  clouds  are  rising  and  dry  weather 
is  indicated. 

If  cirrus  clouds  dissolve  and  appear  to  vanish 
it  is  an  indication  of  fine  weather. 

Clouds  flying  against  the  wind  indicate  rain; 
but  a  clear  sky  before  the  wind  is  a  promise 
that  the  rain  will  soon  end  and  the  weather  clear. 

If  clouds  at  the  same  height  drive  up  with 
the  wind  and  gradually  become  thinner  and 
descend,  it  is  a  promise  of  fair  weather. 

When  on  a  clear  day  "isolated  clouds  drive 
over  the  zenith  from  the  rain-wind  side  [this 
at  most  places  would  be  from  some  point  be- 
tween northeast  and  south]  rain  or  snow  will 
follow  within  twenty-four  hours — more  likely 
within  a  few  hours." 

When  a  heavy  cloud  comes  up  in  the  south- 
273 


OUR   OWN    WEATHER 

west  and  seems  to  settle  back  again  look  out 
for  a  storm. 

"Well-defined  cumulus  clouds  [the  clouds 
that  come  in  heaps]  forming  a  few  hours  after 
sunrise,  increasing  toward  the  middle  of  the 
day  and  decreasing  toward  evening,  are  in- 
dicative of  settled  weather;  if,  instead  of  sub- 
siding in  the  evening  and  leaving  the  sky 
clear,  they  keep  increasing,  they  are  indicative 
of  wet  weather." 

"Clouds  upon  hills,  if  rising,  do  not  bring 
rain;  if  falling,  rain  follows." 

"Enough  blue  sky  in  the  northwest  to  make 
the  Scotchman  a  jacket  is  a  token  of  clear 
weather." 

"When  the  sun  in  the  morning  is  breaking 
through  the  clouds  and  is  scorching,  a  thunder- 
storm follows  in  the  afternoon." 

Soft-looking,  dimly  defined,  delicately  tinted 
clouds  indicate  fair  weather.  Clouds  of  hard, 
defined  outline  and  of  strong  color,  especially 
black  or  black  with  a  cast  of  green,  indicate 
rain  with  probably  high  wind. 

Fog,  which  is  only  near-by  cloud,  is  oftener 
than  not  the  product  of  established  dry  weather, 
and  a  morning  fog  is  a  sure  sign  of  a  day  with- 
out rain.  In  like  manner  heavy  dew  or  heavy 
274 


SIGNS    AND   SUPERSTITIONS 

frost  at  night  gives  promise  of  a  fair  day  to 
follow,  because  dew  and  frost  come  only  in 
fair  weather. 


The  Weather  and  the  Colors  of  the  Sky 

Ordinary  observation  has  gathered  a  great 
number  of  weather  signs  from  simply  the  ever- 
varying  colors  of  the  sky.  Among  the  more 
familiar  and  reliable  ones  are: 

A  bright-blue  sky  is  the  sky  of  fine  weather. 
A  bright-yellow  sky  at  sunset  promises  wind; 
a  pale-yellow  sky  rain,  and  a  "sickly,  greenish" 
sky  both  wind  and  rain.  A  rosy  sky  at  sunset 
promises  fair  weather.  But  a  dark-red  sky  at 
sunset  promises  rain.  A  red  sky  in  the  morning 
promises  wind  or  rain.  "A  red  sun  has  water 
in  his  eye." 

"If  the  sun  sets  in  dark,  heavy  clouds,  expect 
rain  the  next  day."  Even  a  gray  sunset  in- 
dicates rain.  But  a  gray  morning  indicates  a 
fine  day. 

"When  the  sun  draws  water  rain  follows 
soon." 

And,  finally,  what  in  this  connection  it  would 
be  perhaps  the  most  reproachful  of  all  possible 
omissions  not  to  mention: 
275 


OUR   OWN    WEATHER 

Rainbow  at  night, 
Sailor's  delight; 
Rainbow  in  the  morning, 
Sailor's  warning. 

Conclusion 

The  weather  signs  and  maxims  make  as  a 
whole  such  a  volume  and  are  many  of  them  so 
quaint  and  impossible  that  we  have  come  to 
regard  them  as  somewhat  of  a  jest.  But  many 
of  them  have  true  value  and,  with  more  atten- 
tion to  them,  could  be  made  of  much  greater  ser- 
vice in  our  every-day  life  and  affairs  than  they 
are.  Even  people  who  are  under  no  practical 
need  to  attend  much  to  the  weather  would  do 
well  to  have  some  store  of  them,  and  especially  of 
the  quainter  ones,  in  ready  memory.  The  re- 
call of  them  and  the  matching  them  with  and 
against  the  weather  itself  so  helps  to  make  it 
interesting  and  pleasant.  And  to  have  it  in- 
teresting and  pleasant  is,  since  we  must  all 
the  time  live  in  its  embraces,  the  most  compre- 
hensive of  all  domestic  felicities.  It  is  as  a 
friendly  provocation  and  encouragement  to  this 
good  relation  that  these  pages  have  been  written 
by  one  whose  claim  on  his  subject  is,  it  may  be 
confessed,  less  that  of  mastery  than  of  fondness. 


INDEX 


Air,  constitution,  27,  28,  33; 
condenses  and  expands 
easily,  28;  on  mountain 
peaks,  47. 

Amarillo,  Texas,  wind  record, 
193- 

Anticyclone,  an  area  of  high 
pressure,  69,  75;  and  fair 
weather,  97-100,  106;  ex- 
tent, 99,  100 ;  form,  100, 
101;  course,  102,  103;  fre- 
quency, 1 06;  north  Atlan- 
tic, 123,  124,  125;  in  au- 
tumn, I57;^cold,  164,  166; 
hot,  1 66,  170. 

Anti-trade  winds,  18. 

April  weather,  151,  153,  154. 

Areas  of  high  and  low  pres- 
sure, 45,  46. 

Aridity,  region  of,  6,  7. 

Atmosphere,  its  impurities, 
25,  26;  constitution,  26-29; 
extent  and  temperature,  29- 
36;  hot  and  cold  piles  in, 
44-48;  variations,  174-177. 

Aurora  borealis,  219. 

Autumn,  advance  of,  155,  156, 
158. 


B 

Balloons,  flights  of,  34,  35. 
Barometer  records,   53;    and 

cyclones,  98;    fall  of,  and 

rain,  266-270. 
Blizzard,  163,  194,  235. 


Candlemas  Day,  262,  263. 

Central  pour,  97,  98. 

"Chinook"  wind,  193-195. 

Cleveland,  Prof.  Abbe,  calcu- 
lations, 257,  258. 

Cloud-bursts,  248;  signs,  271- 
275- 

Clouds,  conditions  for,  199; 
midday,  201-204;  stratus, 
204,205;  evening,  205-207; 
cirrus,  78-80,  130,  207-210, 
272,  273;  cumulus,  107, 
210-215,  274;  colors  of, 
215-219;  "thunder-heads," 
246. 

Coldest,  month,  140,  142,  155; 
part  of  the  country,  143, 
223. 

Cold,  record,  5,  6;  wave,  159- 
166,  171. 


277 


OUR    OWN    WEATHER 


Colorado,  high  mountain 
peaks,  51. 

Cool  summer,  172-174. 

Cumulus  clouds,  202,  206, 
210-215,  274. 

Cyclones,  cause,  52-56;  and 
tornadoes,  56-58;  not  vio- 
lent, 57;  extent,  58-61; 
frequency,  59 ;  direction, 
60,  61,  69,  71;  European, 
65;  form,  61,  62,  101;  up- 
ward limit,  65;  where  they 
start,  67,  68,  69;  govern- 
ment charts  of,  71;  speed, 
72-75;  few  reach  Great 
Britain,  74;  and  "storm," 
74;  grand  function,  75;  ef- 
fect on  temperature,  77; 
cause  of  cloudiness,  78-80; 
and  rain,  80-84;  height, 
128;  in  March,  152;  in 
April,  153;  increase  in  au- 
tumn, 156;  and  cold  wave, 
159-166;  and  hot  wave,  170. 

Cyclonic  winds,  188,  189. 


Dew,  107,  221,  222,  274. 

Doldrums,  the,  18,  119,  121, 

122. 

Droughts,  historic,  236,  237. 

"Dust"  in  the  air,  30,  157, 
208,  224;  and  radiation,  42, 
43;  and  colors  in  the  sky, 
215,  216. 

E 

Earth's  rotation,  effects  of, 
13,  22-24,  49- 


Equatorial  calm,  belt  of,  18, 

19. 

Equinoctial  storm,  156. 
European  cyclone,  65. 


February,  cold,  140,  141. 

Floods,  cause,  237-240;  of 
1913,  254-258. 

Flying  -  machine,  highest 
flights,  33. 

Fog,  cause,  108;  a  cloud  form- 
ation, 204,  205,  206;  signs, 
274. 

Frost,  107,  108,  222-224,  275. 


Galveston  storm,  its  start, 
135;  loss  of  life  and  prop- 
erty, 136. 

Great  Lakes,  and  the  advance 
of  spring,  154;  and  cloudi- 
ness, 199. 

Ground-hog,  and  the  weather, 
262. 

Gulf  Stream,  warmth  of,  147, 
148. 

H 

Hail-storms,  236. 

Heat,  highest  record,  5. 

High  pressure,  69,  71,  98. 

Horse  latitudes,  19. 

Hot  wave,  166-171. 

Huron,  South  Dakota,  wind 

record,  193. 
Hurricane,  the  West  Indian, 

119,  120,  124-128,  132,  135, 


278 


INDEX 


251 ;  of  tropical  origin,  119- 
120;  average,  120;  rota- 
tion, 121;  season  and  course, 
121-123;  path,  124,  125; 
speed,  125,  126,  129;  rec- 
ord, 127;  diameter,  128; 
height,  128;  behavior,  129; 
forewarnings  of,  130,  131; 
rain  area,  131,  132;  how 
they  operate  in  the  United 
States,  132-134;  visita- 
tions, 134;  record  storms, 
135-137;  in  autumn,  134, 
156. 
Hydrogen,  28. 


Indiana,  1913  flood,  257. 
Indianola  demolished,  135. 
Indian  summer,  157. 
Isothermal  region,  34,  35. 


January,  coldest  month,  140- 
142,  155;  distribution  of 
temperature,  142-145. 

July,  warmest  month,  142, 
155;  distribution  of  tem- 
perature, 148-150. 


Land,  readily  absorbs  heat, 
39;  effect  of  temperature 
on,  41,  47,  48. 

Lightning,  in  thunder-storms, 
248;  damage  and  fatalities, 
248,  249;  frequency,  249; 


the    dangerous,    250;     and 
different    soils,    250;     and 
trees,  250;   rods,  250,  251. 
Low  pressure,  59,  62,  67. 

M 

Mackerel  scales,  272. 
Mammoth  Tank,   California, 

heat  record,  5. 
Map,  the  daily  weather,  54. 
March  winds,  151-153. 
Mare's  tails,  272. 
Maxims,  weather,  261-266. 
Moon  and  the  weather,  260, 

261. 
Mt.  Whitney,  51. 

N 

New    England,    advance    of 

spring  in,  154. 
Nitrogen,  27,  28. 


Ocean,  influence  of,  145,  146. 
Ohio,  1913  flood,  257. 
Omaha,  Nebraska,   1913  tor- 
nado, 255,  256. 
Oxygen,  27,  28. 


Rain,  excessive,  7;  cause,  80^ 
84;  area,  in  hurricanes, 
131,  132;  fall  in  summer, 
150;  average  fall,  220,  221, 
227-229;  formation,  2267 
227;  measuring,  227;  dis- 
tribution, 229-232;  ex- 


279 


OUR   OWN    WEATHER 


cesses,  236,  237;  from 
thunder-storms,  242 ;  and 
fall  of  barometer,  269,  270; 
signs  of,  269-276. 

Rainbow,  219. 

Raindrops,  measurement,  225. 

Roaring  Forties,  20. 


Sea-breezes,  187,  188. 
Seasons,  changes  of,  138-158, 

178-180. 

Signs,  weather,  259-276. 
Sky,  colors  of,  215-219,  275, 

276. 
Snow,   due   to   cyclones,    75; 

its    fall,    232;     form,    233; 

distribution,  234,  235 ;  large 

falls,  235. 

Solar  radiance,  n,  12,  30. 
Spring,  advance  of,  151-154, 

157- 
Storm,    region,    31;     record, 

135-137. 

Stratus  clouds,  204,  205,  215. 
St.    Lawrence   valley,    storm 

section,  68,  72,  73,  154. 
Summer  weather,    139,    148- 

150,  175- 
Sun,  spots,  12,  176;   rise,  50, 

217;  begins  summer  course, 

139;    begins  winter  course, 

139;    crosses   the  equator, 

156. 
Sun's  rays,  effects  on  water, 

38,  41;  on  land,  39,  41,  47; 

on  temperature,  139. 
Sunshine,  solar  radiance,   n, 

12;   distribution,  198-201. 


Temperature,  region  of  low- 
est, 6;  greatest  range  of 
daily,  40,  41;  effect  of 
changes  of,  on  land,  41;  on 
water,  41 ;  average  January, 
142-145;  average  July,  148- 
150. 

Thunder,  reach  of,  247. 

Thunder-storms,  cause,  241- 
243;  speed,  244;  size,  245; 
"heat,"  245,  246;*  fore- 
runner, 246;  rainfall,  242, 
247,  248;  wind,  248;  light- 
ning and  its  fatalities,  248- 
251- 

Tornado,  compared  with  cy- 
clone, 56,  57;  violence,  251; 
width,  251;  speed,  251; 
season  for,  252 ;  cause,  252- 
253;  average,  253;  loss  of 
life  and  property  by,  254, 
255.  256;  of  1913,  254- 
258. 

Trade- winds,  14-22;  direc- 
tion, 15,  16,  21 ;  range,  17; 
anti-,  1 8. 

Tropic,  of  Capricorn,  13;  of 
Cancer,  13. 

Typhoons,  120. 


Velocity  of  wind,  189-193; 
classified,  190,  191. 

Volcano,  California,  heat  rec- 
ord, 5. 


280 


INDEX 


w 

Warm  weather,  172-174. 

Warmest,  month,  142,  155; 
part  of  the  day,  139;  part 
of  the  year,  139;  part  of  the 
country,  149. 

Water,  hard  to  heat,  37,  38; 
effect  of  changes  of  tempera- 
ture on,  41. 

Water- vapor,  26,  28,  31,  80, 
220. 

Weather  Bureau,  85-86,  in, 
132,  135,  158,  165,  191,235, 
236,  250,  269,  270. 

Weather,  in  United  States,  i- 
10,  49,  109;  at  large,  11-24; 
map,  54,  87,  89,  91,  93,  95, 
113,  115,  117;  winter  and 
summer,  138-158;  proph- 
ets, 259;  the  moon  and  the, 
259-261;  maxims,  261-266; 
barometer  signs,  264-269; 


cloud  signs,  271-275;  and 
the  colors  of  the  sky,  275, 
276. 

West  Indian  hurricane,  119, 
120,  124-128,  132,  135,  166, 
175,  251. 

Wind,  in  hurricanes,  128-131;! 
in  thunder-storms,  247,  248; 
as  a  warning  to  the  weather, 
270,  271. 

Winds,  trade,  14-22;  and 
earth's  rotation,  22-24;  di- 
rection, 181,  182;  in  differ- 
ent parts  of  the  country, 
182-187;  cyclonic,  187- 
189;  velocity,  189-193; 
special,  193;  "northers," 
193;  the  "  chinook,"  194- 
195;  increase  with  eleva- 
tion, 196;  automatic  de- 
vices for  recording,  197. 

Winter,  weather,  1 39  - 1 48 ; 
passing  into  summer,  151. 


THE     END 


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